Glandular Trichomes in Satureja thymbra Leaves

The leaves of the aromatic plant Satureja thymbra have numerousglandular trichomes of two morphologically distinct types glandularhairs and glandular scales Investigations of the anatomy ofthese glandular trichomes with serial thick sections revealedthat the glandular hairs consist of three cells a foot, stalkand head cell Glandular scales also have a unicellular footand stalk Their heads, however, are composed of 12 cells Fourof these cells are small, occupying the central region of thehead, whereas the remainder are large and peripherally arrangedMorphometric analysis showed that, in leaf surface view, glandularscales are about 17-fold larger than glandular hairs In addition,glandular scales were found to occupy 5 7 % of the entire leafsurface area In each glandular scale the total amount of essentialoil, contained within both the subcuticular space and the interiorof the secretory cells, was calculated to be 2 51 x 10^–4mm³ The volume of the essential oil produced by all glandularscales on a single mature leaf was correspondingly determinedto be 0.059 mm³ Finally, the theoretical essential oil yieldof 100 g dry leaves of S thymbra was estimated to be 3 54 %(secretory activity of glandular scales only) Satureja thymbra, glandular trichomes, morphology, morphometry     

Functional and Structural Properties of Ovomucin

Relationships between the structural (hydrophobicity and viscosity) and functional (foaming and emulsifying) properties of proteins were investigated by using a polymeric form of ovomucin (soluble type), and dissociated ovomucins which were treated with sonication (sonicated type) and reduction (reduced type). The soluble, sonicated and reduced ovomucins were ascertained to have excellent foaming and emulsifying properties. The foaming properties of the ovomucins decreased in proportion to decreases in the viscosity as the dissociation proceeded, in the order of the soluble, sonicated and reduced types. On the other hand, the emulsifying properties of ovomucins increased in proportion to increases in the surface hydrophobicity as the dissociation proceeded.

Thus, it was suggested that the foaming properties of ovomucins were dependent upon viscosity, and that the emulsifying properties of ovomucins were dependent upon surface hydrophobicity.     

The Structural and Functional Properties of Z-DNA

Biophysics - This review covers the stages of studying left-helical Z-DNA form, from its discovery in 1979 until the present time. The repetitive nucleotide sequences that are capable of the...     

Kinetic and Structural Properties of NADP-Malic Enzyme from Sugarcane Leaves

Oligomeric structure and kinetic properties of NADP-malic enzyme, purified from sugarcane (Saccharam officinarum L.) leaves, were determined at either pH 7.0 and 8.0. Size exclusion chromatography showed the existence of an equilibrium between the dimeric and the tetrameric forms. At pH 7.0 the enzyme was found preferentially as a 125 kilodalton homodimer, whereas the tetramer was the major form found at pH 8.0. Although free forms of l-malate, NADP⁺, and Mg²⁺ were determined as the true substrates and cofactors for the enzyme at the two conditions, the kinetic properties of the malic enzyme were quite different depending on pH. Higher affinity for l-malate (K_m = 58 micromolar), but also inhibition by high substrate (K_i = 4.95 millimolar) were observed at pH 7.0. l-Malate saturation isotherms at pH 8.0 followed hyperbolic kinetics (K_m = 120 micromolar). At both pH conditions, activity response to NADP⁺ exhibited Michaelis-Menten behavior with K_m values of 7.1 and 4.6 micromolar at pH 7.0 and 8.0, respectively. Negative cooperativity detected in the binding of Mg²⁺ suggested the presence of at least two Mg²⁺ - binding sites with different affinity. The K_a values for Mg²⁺ obtained at pH 7.0 (9 and 750 micromolar) were significantly higher than those calculated at pH 8.0 (1 and 84 micromolar). The results suggest that changes in pH and Mg²⁺ levels could be important for the physiological regulation of NADP-malic enzyme.     

Structural and Functional Damage Caused by Boron Deficiency in Sunflower Leaves

Boron deficiency induced a dramatic inhibition in sunflower plant growth, shown by a reduction in dry mass of roots and shoots of plants grown for 10 d in nutrient solution supplied with 0.02 μM B. This low B supply facilitated the appearance of brown purple pigmentation on the plant leaves over the entire growth period. Compared to B-sufficient (BS) leaves, leakage from B-deficient (BD) leaves was 20 fold higher for potassium, 38 fold for sucrose, and 6 fold for phenolic compounds. High level of membrane peroxidation was detected by measuring peroxidase activities as well as peroxidative products in BD sunflower plants. Soluble and bound peroxidase activities measured in BD thylakoid membranes were accelerated two fold compared to those detected in BS-membranes. No detectable change in soluble peroxidase activity in roots whereas a 4 fold stimulation in bound peroxidase activity was detected. Thylakoid membranes subjected to low B supply showed enhancement in lipoxygenase activity and malondialdehyde (MDA) content in parallel with 40 and 30 % decrease of linoleic and linolenic acid contents (related to total unsaturated fatty acids). A slower rate of Hill reaction activity (40 %) and a suppressed flow of electron transfer of the whole chain (30 %) were detected in BD thylakoid membranes. This reduction was accompanied with a decline in the activity of photosystem 2 shown by a diminished rate of oxygen evolution (42 %) coupled with a quenching (27.5 %) in chlorophyll a fluorescence emission spectra at 685 nm (F₆₈₅). Thus B is an important element for membrane maintenance, protection, and function by minimizing or limiting production of free oxygen radicals in thylakoid membranes of sunflower leaves. This revised version was published online in June 2006 with corrections to the Cover Date.     

Structural and Functional Damage Caused by Boron Deficiency in Sunflower Leaves

Photosynthetica - Boron deficiency induced a dramatic inhibition in sunflower plant growth, shown by a reduction in dry mass of roots and shoots of plants grown for 10 d in nutrient solution...     

Structural and Histochemical Investigation of the Glandular Trichomes of Salvia aurea L. Leaves, and Chemical Analysis of the Essential Oil

Anatomical and histological investigations of the secretoryhairs ofSalvia aurea leaves, and identification of the maincomponents of the essential oil were carried out. Two typesof glandular trichome were found: peltate glands, characterizedby a short stalk and a large six to eight-celled head, and capitatetrichomes which were further subdivided into two kinds, thefirst with a short monocellular stalk and two-cellular head(type I), and the second with a multicellular stalk, a neckcell and a small globose unicellular head (type II). Whereaspeltate glands and type I capitate trichomes were always present,type II capitate glands were not found in all leaf samples.The histochemical study suggested an ‘endodermal’role for the stalk cell (peltate and capitate type I) as wellas for the neck cell (capitate type II), preventing the lossof essential oil. Histological reactions also revealed the complexnature of the material secreted by all types ofS. aurea trichome,including polysaccharides, polyphenols and proteins, in additionto the essential oil. Qualitative and quantitative GC-MS analysisof the essential oil revealed camphor to be the main constituent.The findings are discussed in relation to studies of trichomesfrom other members of the Lamiaceae. Salvia aurea L.; glandular trichomes; histochemistry; essential oil     

The Ultrastructure of Glandular Trichomes ofPhillyrea latifoliaL. (Oleaceae) Leaves

The anatomy and ultrastructure of glandular trichomes at differentdevelopmental stages were investigated inPhillyrea latifoliaL.leaves by transmission electron microscopy and histochemicaltechniques. The trichome consisted of a multicellular secretoryhead, a unicellular stalk and a collecting cell surrounded byepidermal cells and spongy mesophyll cells. There were numerousplasmodesmata across the cell walls of trichome cells, and especiallybetween the stalk cell and the collecting cell. The collectingcell and stalk cell contained few chloroplasts. Mitochondria,elements of the endoplasmic reticulum and small vacuoles wereabundant in the secretory cells. Crystals were present in thesecretory cells and the collecting cell, especially at the matureand senescent stages of trichome development. As the cuticle,which covered the secretory cells, did not show pores or perforations,it is proposed that secretion occurred by accumulation of productsin subcuticular spaces followed by diffusion through the cuticle.Callose accumulation was observed between the stalk cell andthe collecting cell of senescent trichomes, especially in salt-treatedplants. Trichome ontogeny was accelerated in salt-treated plants.Copyright1998 Annals of Botany Company Cuticle;Phillyrea latifolia; secretion; transmission electron microscopy; trichome development.     

Sleep-Inducing Properties of DSIP Analogs: Structural and Functional Relationships

The sleep-inducing activity of Delta Sleep-Inducing Peptide (DSIP) and its 13 synthetic analogs has been studied on rabbits with preliminary implanted electrodes. The peptides were injected into the lateral ventricle of cerebrum. Polygraphic computer monitoring of sleep–wake states was carried out at daytime for 7–12 h. DSIP and most analogs had no statistically significant effect on sleep compared to the control administration of saline to the same animals. [NMeAla²]DSIP and [Pro²]DSIP had a pronounced sleep-inducing effect and reliably increased the proportion of slow-wave sleep by 10–15% on average compared to the control. Several other analogs had a week sleep-inducing effect, increasing the proportion of slow-wave sleep during specific recording time only. [-Ala²]DSIP significantly suppressed sleep. In addition, this analog, as well as parent DSIP and four proline-containing nonapeptides, slightly increased the body temperature. The revealed differences may be due to both conformation properties and proteolytic resistance of the studied molecules, and it may reflect their indirect involvement in the control sleep–wake hormonal processes.     

Distinct Functional Properties of Isoamylase-Type Starch Debranching Enzymes in Monocot and Dicot Leaves

Isoamylase-type starch debranching enzymes (ISA) play important roles in starch biosynthesis in chloroplast-containing organisms, as shown by the strict conservation of both catalytically active ISA1 and the noncatalytic homolog ISA2. Functional distinctions exist between species, although they are not understood yet. Numerous plant tissues require both ISA1 and ISA2 for normal starch biosynthesis, whereas monocot endosperm and leaf exhibit nearly normal starch metabolism without ISA2. This study took in vivo and in vitro approaches to determine whether organism-specific physiology or evolutionary divergence between monocots and dicots is responsible for distinctions in ISA function. Maize (Zea mays) ISA1 was expressed in Arabidopsis (Arabidopsis thaliana) lacking endogenous ISA1 or lacking both native ISA1 and ISA2. The maize protein functioned in Arabidopsis leaves to support nearly normal starch metabolism in the absence of any native ISA1 or ISA2. Analysis of recombinant enzymes showed that Arabidopsis ISA1 requires ISA2 as a partner for enzymatic function, whereas maize ISA1 was active by itself. The electrophoretic mobility of recombinant and native maize ISA differed, suggestive of posttranslational modifications in vivo. Sedimentation equilibrium measurements showed recombinant maize ISA1 to be a dimer, in contrast to previous gel permeation data that estimated the molecular mass as a tetramer. These data demonstrate that evolutionary divergence between monocots and dicots is responsible for the distinctions in ISA1 function.Semicrystalline starch enables photosynthetic eukaryotes to store large quantities of Glc over extended time periods compared with other species, in which the soluble polymer glycogen functions to store carbohydrate reserves (Ball and Morell, 2003). Eukaryotes gained the capacity to photosynthesize after the capture of a cyanobacterial endosymbiont by a glycogen-metabolizing host cell. In the lineage that evolved subsequently, known as the Archaeplastida, select glucan-storage enzymes encoded within the host nucleus, the endosymbiont, and potentially a prokaryotic parasite located within the host cell developed so as to generate the branched glucan polymer amylopectin (Ball et al., 2011, 2013). Such molecules are highly similar to glycogen in terms of chemical structure, but the molecular architecture of amylopectin enables the formation of semicrystalline structures (Buléon et al., 1998). These latter then assemble into higher order structures leading to starch granule formation. The advent of starch granules is likely to have been critical for the evolution of chloroplast-containing organisms, including the spread of land plants on the Earth’s surface, because they enable the storage of photosynthetically generated Glc for many hours in tissues such as leaves during diurnal cycles or for months to years in seeds.An important aspect of the evolutionary change from glycogen to starch is the use of particular α(1→6)-glucosidases, referred to as isoamylase-type starch debranching enzymes (ISA), in the production of amylopectin (Ball et al., 1996; Myers et al., 2000; Hennen-Bierwagen et al., 2012). A suite of genes encoding the enzymes that accomplish starch biosynthesis was established early in the evolution of chloroplast-containing organisms (i.e. the Chloroplastida) prior to the divergence of distantly related groups including green algae and land plants. Included in this gene set are three paralogs that encode the proteins ISA1, ISA2, and ISA3, each of which is highly conserved in chloroplast-containing species. ISA1 of vascular plants and bryophytes, for example, are approximately 70% identical over more than 600 residues, and between land plants and prasinophyte algae this value is about 60%. ISA1 or ISA2 deficiencies in potato (Solanum tuberosum) tuber, Arabidopsis (Arabidopsis thaliana) leaf, Chlamydomonas reinhardtii cells, and cereal endosperms result in reduced starch content, altered amylopectin structure, and the appearance of soluble, branched glucans similar to native glycogen (James et al., 1995; Mouille et al., 1996; Nakamura et al., 1996; Bustos et al., 2004; Delatte et al., 2005; Wattebled et al., 2005). Such soluble polymers, referred to as phytoglycogen, have not been observed in wild-type plants. Thus, ISA1 and ISA2 functions are important determinants of whether storage glucans are semicrystalline or soluble. ISA3, in contrast, functions primarily in starch catabolism (Wattebled et al., 2005; Delatte et al., 2006).ISA1 and ISA2 appear to function together in Arabidopsis leaf as a single entity, because essentially identical phenotypes are observed in single mutants lacking either protein or double mutants lacking both of them (Zeeman et al., 1998; Delatte et al., 2005; Wattebled et al., 2005). Biochemical analysis of native and recombinant proteins has shown directly that ISA1 and ISA2 function together in a complex. ISA activity was first purified from potato tuber and found to contain two distinct polypeptides identified as ISA1 and ISA2 (Ishizaki et al., 1983; Hussain et al., 2003). Heteromultimers containing these two proteins were also purified from rice (Oryza sativa) and maize (Zea mays) endosperm (Utsumi and Nakamura, 2006; Kubo et al., 2010). Finally, a mixture of native and recombinant rice proteins demonstrated directly that specific enzymatic activities are provided by ISA1 and ISA2 functioning together in a heteromultimeric complex (Utsumi and Nakamura, 2006). ISA1 is the catalytic subunit within this complex, whereas ISA2 is noncatalytic, owing to amino acid substitutions at residues that are essentially invariant in the GH13 family of glycoside hydrolases (i.e. the α-amylase superfamily), several of which participate in the catalytic mechanism (Hussain et al., 2003; Utsumi and Nakamura, 2006). Despite lacking catalytic activity, ISA2 proteins are conserved in all chloroplast-containing species that have been examined, which rules out recently evolved mutations and, to the contrary, suggests a functional selective advantage.The necessity for the ISA1/ISA2 heteromultimer is not obvious in light of the fact that, in some instances, ISA1 by itself can condition normal levels of starch and the suppression of phytoglycogen accumulation. Cyanidioschyzon merolae, a species within the Rhodophyta lineage of the Archaeplastida family, contains semicrystalline starch and amylopectin with physical characteristics similar to that of Chloroplastida species (Hirabaru et al., 2010). The C. merolae genome contains elements that encode ISA1 and ISA3 yet lacks a homolog encoding ISA2 (Coppin et al., 2005). Thus, in some instances, starch can be generated, and phytoglycogen accumulation suppressed, without an ISA2 protein. Cereal endosperms provide additional evidence that ISA2 is not strictly required for normal starch levels and the suppression of phytoglycogen accumulation. Mutants or transgenic lines lacking ISA2 are known in rice (Utsumi et al., 2011) and maize (Kubo et al., 2010). Endosperm from these plants exhibits normal starch levels, with amylopectin structure essentially the same as the wild type, and lacks phytoglycogen. ISA activity presumably is provided in the endosperm of these mutants by a homomultimeric enzyme containing only ISA1.The reason why ISA2 is strictly conserved in the Chloroplastida is not understood yet. Two explanations can be considered. One possibility is that the inherent structure of ISA1 in cereals, resulting from mutations accumulated specifically in this evolutionary lineage, allows it to act without ISA2. Another possibility is that metabolic differences in specific tissues (e.g. leaf versus endosperm) require specialized enzymatic properties of the ISA1/ISA2 heteromer that ISA1 by itself does not provide. To test these hypotheses, this study combined maize and Arabidopsis ISA1 and ISA2 isoforms both in vitro and in vivo. Maize ISA1 was found to be active without any ISA2 protein, either in vitro or in Arabidopsis leaves, whereas Arabidopsis ISA1 required an ISA2 partner in all instances. Thus, ISA1 appears to have evolved in the cereal lineage so that it no longer requires ISA2 for enzymatic activity or metabolic function in the generation of starch and the suppression of phytoglycogen accumulation.     

JunD的结构功能特征及其在肿瘤发展中的作用

JunD是一种属于多功能激活剂蛋白-1（activating protein-1,AP-1) 家族的转录因子,可以激活或抑制多种靶基因的表达.在生长发育过程中,在各种细胞类型中都呈现出组成性表达.近20年的临床数据及分子生物学研究表明,JunD蛋白的功能受多个复杂过程调控,包括转录控制、转录后调节、蛋白质翻译后修饰及蛋白-蛋白相互作用等.JunD基因表达的精细调控及JunD蛋白与其它蛋白之间的相互作用可调节细胞增殖、分化和凋亡等过程.JunD蛋白活性异常会导致肿瘤、代谢及病毒类疾病的发生.JunD蛋白的转录激活及抑制受1个复杂调控网络调控,在这个网络调节下,JunD蛋白在细胞的生长调控过程中发挥重要作用.本文就JunD基因表达的调控机制及其与肿瘤之间关系的最新研究进展做一综述.     

Glandular Trichomes on the Leaves and Flowers of Plectranthus ornatus: Morphology, Distribution and Histochemistry

The types of glandular trichomes and their distribution on leavesand flowers of Plectranthus ornatus were investigated at differentstages of their development. Five morphological types of glandulartrichomes are described. Peltate trichomes, confined to theleaf abaxial surface, have, in vivo, an uncommon but characteristicorange to brownish colour. Capitate trichomes, uniformly distributedon both leaf surfaces, are divided into two types accordingto their structure and secretory processes. In long-stalkedcapitate trichomes, a heterogeneous secretion (a gumresin) isstored temporarily in a large subcuticular space, being releasedby cuticle rupture, whereas, in the short-stalked capitate trichomes,the secretion, mainly polysaccharidic, is probably exuded viamicropores. On the leaves, digitiform trichomes, which do notshow a clear distinction between the apical glandular cell andthe subsidiary cells, occur with a similar distribution to thecapitate trichomes. They do not develop a subcuticular space,and secrete small amounts of essential oils in association withpolysaccharides. The reproductive organs, particularly the calyxand corolla, exhibit, in addition to the reported trichomes,unusual conoidal trichomes with long unicellular conical heads.A large apical pore, formed by tip disruption, releases thesecretion (a gumresin) stored in a rostrum-like projection.On the stamens and carpels, digitiform, capitate and conoidaltrichomes are absent, but peltate trichomes are numerous. Theyoccur between the two anther lobes, on the basal portion ofthe style, and between the four lobes of the ovary. The resultspresented are compared with those of other studies on Lamiaceaeglandular trichomes. Copyright 1999 Annals of Botany Company Plectranthus ornatus Codd, Lamiaceae, glandular trichomes, morphology, histochemistry, essential oils and mucilage secretion.     

Unique Functional and Structural Properties of the LRRK2 Protein ATP-binding Pocket

Pathogenic mutations in the LRRK2 gene can cause late-onset Parkinson disease. The most common mutation, G2019S, resides in the kinase domain and enhances activity. LRRK2 possesses the unique property of cis-autophosphorylation of its own GTPase domain. Because high-resolution structures of the human LRRK2 kinase domain are not available, we used novel high-throughput assays that measured both cis-autophosphorylation and trans-peptide phosphorylation to probe the ATP-binding pocket. We disclose hundreds of commercially available activity-selective LRRK2 kinase inhibitors. Some compounds inhibit cis-autophosphorylation more strongly than trans-peptide phosphorylation, and other compounds inhibit G2019S-LRRK2 more strongly than WT-LRRK2. Through exploitation of structure-activity relationships revealed through high-throughput analyses, we identified a useful probe inhibitor, SRI-29132 (11). SRI-29132 is exquisitely selective for LRRK2 kinase activity and is effective in attenuating proinflammatory responses in macrophages and rescuing neurite retraction phenotypes in neurons. Furthermore, the compound demonstrates excellent potency, is highly blood-brain barrier-permeant, but suffers from rapid first-pass metabolism. Despite the observed selectivity of SRI-29132, docking models highlighted critical interactions with residues conserved in many protein kinases, implying a unique structural configuration for the LRRK2 ATP-binding pocket. Although the human LRRK2 kinase domain is unstable and insoluble, we demonstrate that the LRRK2 homolog from ameba can be mutated to approximate some aspects of the human LRRK2 ATP-binding pocket. Our results provide a rich resource for LRRK2 small molecule inhibitor development. More broadly, our results provide a precedent for the functional interrogation of ATP-binding pockets when traditional approaches to ascertain structure prove difficult.     

革兰氏阴性菌血红素转运系统结构及功能特点

铁是大多数生物包括细菌生存的必需营养元素．对于感染宿主的致病细菌,血红素(heme/haem)可作为一种主要的铁来源．血红素转运系统在革兰氏阴性菌和革兰氏阳性菌中均有发现和鉴定,其转运机制在革兰氏阴性菌中有较为深入研究．革兰氏阴性菌血红素转运系统主要由分泌于细胞外的血红素载体(hemophore)、血红素受体、TonB ExbB ExbD复合物、ABC转运体、血红素降解蛋白和调控蛋白等结构单元组成．对参与该系统的各个蛋白结构特点以及它们之间的相互作用机制的讨论,有助于对病原菌致病机制的深入研究和抗菌新药的研发．     

Structural and Functional Properties of Platelet-Derived Growth Factor and Stem Cell Factor Receptors

The receptors for platelet-derived growth factor (PDGF) and stem cell factor (SCF) are members of the type III class of PTK receptors, which are characterized by five Ig-like domains extracellularly and a split kinase domain intracellularly. The receptors are activated by ligand-induced dimerization, leading to autophosphorylation on specific tyrosine residues. Thereby the kinase activities of the receptors are activated and docking sites for downstream SH2 domain signal transduction molecules are created; activation of these pathways promotes cell growth, survival, and migration. These receptors mediate important signals during the embryonal development, and control tissue homeostasis in the adult. Their overactivity is seen in malignancies and other diseases involving excessive cell proliferation, such as atherosclerosis and fibrotic diseases. In cancer, mutations of PDGF and SCF receptors—including gene fusions, point mutations, and amplifications—drive subpopulations of certain malignancies, such as gastrointestinal stromal tumors, chronic myelomonocytic leukemia, hypereosinophilic syndrome, glioblastoma, acute myeloid leukemia, mastocytosis, and melanoma.The type III tyrosine kinase receptor family consists of platelet-derived growth factor (PDGF) receptor α and β, stem cell factor (SCF) receptor (Kit), colony-stimulating factor-1 (CSF-1) receptor, and Flt-3 (Blume-Jensen and Hunter 2001). Members of this receptor family are characterized by five Ig-like domains in their extracellular part, a single transmembrane domain, and an intracellular part consisting of a rather well-conserved juxtamembrane domain, a tyrosine kinase domain with a characteristic inserted sequence without homology with kinases, and a less well-conserved carboxy-terminal tail. The ligands for these receptors are all dimeric molecules, and on binding they induce receptor dimerization. Although the overall mechanisms for the activation of the type III tyrosine kinase receptors and the signaling pathways they induce are similar, the receptors are expressed on different cell types and thus have different functions in vivo.Here we will describe the structural and functional properties of the PDGF receptors and Kit.     

Structural and Functional Properties of Glycerol-3-Phosphate Dehydrogenase from a Mammalian Hibernator

Glycerol-3-phosphate dehydrogenase (G3PDH; E.C.1.1.1.8) was purified from liver and skeletal muscle of black-tailed prairie dogs (Cynomys ludivicianus), a hibernating species. Native and subunit molecular masses of the dimeric enzyme were 77 and 40 kD, respectively, and both tissues contained a single isozyme with a pI of 6.4. Kinetic parameters of purified G3PDH from prairie dog liver and muscle were characterized at 22 and 5 °C and compared with rabbit muscle G3PDH. Substrate affinities for hibernator muscle G3PDH were stable (NAD) or increased significantly (K_m G3P and DHAP decreased) at low temperature whereas K_m NAD and DHAP of rabbit G3PDH increased. Prairie dog G3PDH showed greater conservation of K_m G3P over a wide temperature range as well as greater thermal stability and resistance to chemical denaturation by guanidine hydrochloride than the rabbit enzyme. In addition, using the protein sequence of the hibernating thirteen-lined ground squirrel (Ictidomys tridecemlineatus) and bioinformatics tools, the deduced protein structure of G3PDH was compared between heterothermic and homeothermic mammals. Structural and functional characteristics of G3PDH from the hibernating species would support enzyme function over a wide range of core body temperatures over cycles of torpor and arousal.     

Structural and Functional Properties of Chicken Lysozyme Fused Serine-rich Heptapeptides at the C-Terminus

Two serine-rich heptapeptides, Ser-Ser-Ser-Lys-Ser-Ser-Ser (S6K) and Ser-Ser-Ser-Ser-Ser-Ser-Ser (S7), were fused to the C-terminus of chicken lysozyme (Lz) by genetic modification to improve the functional properties of lysozyme. The cDNAs of S6K-lysozyme (S6K-Lz) and S7-lysozyme (S7-Lz) were inserted into the expression vector of Pichia pastoris and secreted in yeast cultivation medium. The secretion amounts of S6K-Lz and S7-Lz were about 60% of that of wild-type lysozyme (Wt-Lz). The CD spectra showed that the conformation of S6K-Lz and S7-Lz was conserved regardless of the attachment of serine-rich peptides. The denaturation curves of S6K-Lz and S7-Lz also showed that the conformational changes were very small. The lytic activity of S6K-Lz and S7-Lz was almost the same as that of Wt-Lz, while the bactericidal activity against Escherichia coli of S6K-Lz and S7-Lz was greatly increased. The acetic acid-urea PAGE of phosphatase-treated S6K-Lz and S7-Lz indicated the possibility of phosphorylation of the fused serine-rich heptapeptides.