Nucleotide sequence and phylogenetic implication of the ATPase subunits β and ε encoded in the chloroplast genome of the brown alga Dictyota dichotoma

We have cloned and sequenced the genes atpB and atpE, coding for CF₁ subunits and , respectively, of the chloroplast genome of the brown alga Dictyota dichotoma. Although the coding site of atpE cannot be demonstrated by heterologous Southern hybridizations, a 417 bp reading frame 3 to atpB was identified as the gene atpE by sequence similarities with atpE genes from other sources. A maximum sequence identity of 30% is found between the predicted amino acid sequence of the Dictyota subunit and the corresponding cyanobacterial subunits. Including conserved amino acid replacements, the Dictyota subunit exhibits about 70% sequence similarity with the cyanobacterial and land plant subunits. As in cyanobacteria, the atpE gene does not overlap the preceding gene atpB. The deduced amino acid sequence of atpB is 74–79% identical to the corresponding cyanobacterial and chloroplast subunits. Entirely conserved are regions referred to as the catalytic and/or regulatory sites of ATP formation, including interacting regions between subunits and . A phylogram predicted from F₁/CF₁- subunits of eleven different organisms suggests a common evolutionary origin of plastids from chlorophytes and brown algae.     

Regional chromosomal assignment of genes encoding the α and β subunits of human complement protein C8 to 1p32

Summary The genes encoding the and subunits of human complement protein C8 previously mapped to chromosome 1 have been further localised to 1p32 by in situ hybridisation using biotinylated 2.4-kb human cDNA clones encoding the and subunits of human complement protein C8 as probes.     

Identification of heterotrimeric G protein α and β subunits in rice

Like those in mammals, heterotrimeric G protein complexes have been implicated in signal transduction pathways in plants; however, the subunits themselves have not been isolated. In this study, the rice heterotrimeric G protein subunits α (Gα) and β (Gβ) were purified by affinity chromatography using anti-Gα and -Gβ antibodies and SDS-PAGE. Six and seven peptides, respectively, were identified by mass spectrometry and identified as the translation products of the Gα gene RGA1 and Gβ gene RGB1. During purification, the subunits dissociated easily from the G protein complex.     

Isolation, properties and spatial site analysis of γ subunits of B-phycoerythrin and R-phycoerythrin

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Kinetics of the reconstitution of hemoglobin from semihemoglobins α and β with heme

Kinetics of the reconstitution of hemoglobin from semihemoglobins and with hemin dicyanide have been investigated using three kinds of stopped-flow technique (Soret absorption, fluorescence quenching of tryptophan, and Soret CD). The semihemoglobins and are occupied by heme in the and chains, respectively, the other chain being heme-free. Based on the kinetic results, the following scheme for the reconstitution is proposed; First, hemin dicyanide enters the pocket-like site of the apo chains. Second, in semihemoglobin , the CN-ligand in the fifth coordination position of iron is replaced by the imidazole ring of the proximal His immediately after the heme insertion. In contrast, semihemoglobin changes its conformation after the heme insertion, and this is followed by the ligand replacement. Finally, the partial structure changes induced by the ligand replacement propagate onto the whole molecule and the final conformation is attained. The results indicate that semihemoglobin retains a more rigid and organized structure, and more closely approaches its final structure than does semihemoglobin . Correspondence to: Y. Kawamura-Konishi     

Immunohistochemical localization of the α and β subunits of S-100 protein in pleomorphic adenoma of the salivary glands

The immunohistochemical expression of the alpha and beta subunits of S-100 protein in reactive, modified and transformed of myoepithelial cells, salivary pleomorphic was investigated using monoclonal antibodies. With S-100 alpha, normal salivary glands showed strong staining in serous acinar cells and moderate to slight staining in ductal segments, and with S-100 beta staining was slight or negative in acinar cells, but strong in nerve fibres. In pleomorphic salivary adenomas, the immunohistochemical distribution of S-100 alpha and beta proteins indicated great variation in the tumour cells. Some neoplastic cells gave similar staining for both S-100 alpha and beta, others were strongly positive for S-100 alpha and stained only slightly for S-100 beta, or vice versa. Yet other cells were positive for S-100 alpha and negative for S-100 beta, or vice versa. Pleomorphic salivary adenomas were classified both by histopathological criteria and by their staining pattern for S-100 alpha and beta proteins. Great heterogeneity in S-100 alpha and beta protein expression was found in individual tumour cells of both ductal and myoepithelial origin, and no regular pattern was identified. The cellular origin of salivary pleomorphic adenomas is discussed in terms of S-100 alpha and beta protein immunohistochemistry. Pleomorphic adenoma cells may be transformed from reserve cells into tumour cells displaying biologic properties of myoepithelial cells, ductal cells, or a mixture of both.     

Fusion of the subunits α and β of succinyl-CoA synthetase as a phylogenetic marker for Pezizomycotina fungi

Gene fusions, yielding the formation of multidomain proteins, are evolutionary events that can be utilized as phylogenetic markers. Here we describe a fusion gene comprising the α and β subunits of succinyl-coA synthetase, an enzyme of the TCA cycle, in Pezizomycotina fungi. This fusion is present in all Pezizomycotina with complete genome sequences and absent from all other organisms. Phylogenetic analysis of the α and β subunits of succinyl-CoA synthetase suggests that both subunits were duplicated and retained in Pezizomycotina while one copy was lost from other fungi. One of the duplicated copies was then fused in Pezizomycotina. Our results suggest that the fusion of the α and β subunits of succinyl-CoA synthetase can be used as a molecular marker for membership in the Pezizomycotina subphylum. If a species has the fusion it can be reliably classified as Pezizomycotina, while the absence of the fusion is suggestive that the species is not a member of this subphylum.     

Cloning of cDNA,expression, and chromosomal location of genes encoding the three types of subunits of the barley tetrameric inhibitor of insect α-amylase

Three cDNA clones from barley developing endosperm, corresponding to proteins BTAI-CMa, BTAI-CMb and BTAI-CMd, which are the three types of subunits of the tetrameric inhibitor of insect -amylases, have been identified and sequenced. The deduced amino acid sequence of BTAI-CMb corresponds to the CM16/CM17 type of subunit in wheat (92/90% identical residues) and has one putative N-glycosylation site (NLT) and a possible kinase-C phosphorylation site (SCR). The BTAI-CMa sequence differs at four amino acid residues from a previously reported one from cv. Bomi and the sequence deduced for BTAI-CMd completes (11 N-terminal residues) and confirms previously available data. The gene for BTAI-CMa (Iat1) is located in the arm of barley chromosome 7H (syn.1), while genes for both BTAI-CMb (Iat2) and BTAI-CMd (Iat3) are in the long arm of chromosome 4H. The three genes are expressed in endosperm and their mRNAs are not detected in the other tissues tested, except Iat1, which seems to be expressed at a low level in coleoptile and roots, where it is switched off by 50 M methyl jasmonate.     

The nucleotide sequence of the β-glucosidase gene from Cellvibrio gilvus

A gene encoding β-glucosidase from Cellvibrio gilvus, a cellobiose-producing bacterium, was cloned into Escherichia coli and sequenced. The structural gene consisted of 2565 bp encoding 854 amino acid residues with a characteristic signal peptide. A typical promoter sequence and SD region were located upstream of the initiation ATG codon. A sequence (180 amino acids) having high homology with those of β-glucosidases from several microorganisms was found in the deduced amino acid sequence of C. gilvus β-glucosidase. This sequence contains the aspartic acid residue which was found to be an active site residue in Aspergillus wentii β-glucosidase A3. The β-glucosidase gene of C. gilvus contains a high amount (69.4%) of G+C. These bases are localized not in the 3rd position of the codon, as is usually observed in G+C-rich genes, but rather in the 1st position. This result in a peptide which contains an extremely high amount (48%) of four amino acids (Pro, Ala, Arg, Gly) coded by CCN, GCN, CGN, and GGN.     

Regional expression and subcellular localization of the voltage-gated calcium channel β subunits in the developing mouse brain

J. Neurochem. (2012) 122, 1095-1107. ABSTRACT: Ca(2+) channel β subunits determine the maturation, biophysical properties and cell surface expression of high voltage-activated channels. Thus, we have analysed the expression, regional distribution and subcellular localization of the Ca(v) β subunit family in mice from birth to adulthood. In the hippocampus and cerebellum, Ca(v) β(1) , Ca(v) β(3) and Ca(v) β(4) protein levels increased with age, although there were marked region- and developmental stage-specific differences in their expression. Ca(v) β(1) was predominantly expressed in the strata oriens and radiatum of the hippocampus, and only weakly in the cerebellum. The Ca(v) β(3) subunit was mainly expressed in the strata radiatum and lucidum of the hippocampus and in the molecular layer of the cerebellum. During development, Ca(v) β(3) protein expression in the cerebellum peaked at postnatal days (P) 15 and 21, and had diminished drastically by P60, and in the hippocampus increased with age throughout all subfields. Ca(v) β(4) protein was detected throughout the cerebellum, particularly in the molecular layer, and in contrast to the other subunits, Ca(v) β(4) was mainly detected in the molecular layer and the hilus of the hippocampus. At the subcellular level, Ca(v) β(1) and Ca(v) β(3) were predominantly located post-synaptically in hippocampal pyramidal cells and cerebellar Purkinje cells. Ca(v) β(4) subunits were detected in the pre-synaptic and post-synaptic compartments of both regions, albeit more strongly at post-synaptic sites. These results shed new light on the developmental regulation and subcellular localization of Ca(v) β subunits, and their possible role in pre- and post-synaptic transmission.     

Modulating distal cavities in the α and β subunits of human HbA reveals the primary ligand migration pathway

The free volume in the active site of human HbA plays a crucial role in governing the bimolecular rates of O(2), CO, and NO binding, the fraction of geminate ligand recombination, and the rate of NO dioxygenation by the oxygenated complex. We have decreased the size of the distal pocket by mutating Leu(B10), Val(E11), and Leu(G8) to Phe and Trp and that of other more internal cavities by filling them with Xe at high gas pressures. Increasing the size of the B10 side chain reduces bimolecular rates of ligand binding nearly 5000-fold and inhibits CO geminate recombination due to both reduction of the capture volume in the distal pocket and direct steric hindrance of Fe-ligand bond formation. Phe and Trp(E11) mutations also cause a decrease in distal pocket volume but, at the same time, increase access to the Fe atom because of the loss of the γ2 CH(3) group of the native Val(E11) side chain. The net result of these E11 substitutions is a dramatic increase in the rate of geminate recombination because dissociated CO is sequestered close to the Fe atom and can rapidly rebind without steric resistance. However, the bimolecular rate constants for binding of ligand to the Phe and Trp(E11) mutants are decreased 5-30-fold, because of a smaller capture volume. Geminate and bimolecular kinetic parameters for Phe and Trp(G8) mutants are similar to those for the native HbA subunits because the aromatic rings at this position cause little change in distal pocket volume and because ligands do not move past this position into the globin interior of wild-type HbA subunits. The latter conclusion is verified by the observation that Xe binding to the α and β Hb subunits has little effect on either geminate or bimolecular ligand rebinding. All of these experimental results argue strongly against alternative ligand migration pathways that involve movements through the protein interior in HbA. Instead, ligands appear to enter through the His(E7) gate and are captured directly in the distal cavity.     

Cloning,expression, and antiviral activity of interferon β from the Chinese microbat,Myotis davidii

Bats are natural reservoir hosts for many viruses that produce no clinical symptoms in bats.Therefore, bats may have evolved effective mechanisms to control viral replication. However, little information is available on bat immune responses to viral infection. Type I interferon(IFN) plays a key role in controlling viral infections. In this study, we report the cloning, expression, and biological activity of interferon β(IFNβ) from the Chinese microbat species, Myotis davidii. We demonstrated the upregulation of IFNB and IFN-stimulated genes in a kidney cell line derived from M. davidii after treatment with poly I:C or infection with Sendai virus. Furthermore, the recombinant IFNβ inhibited vesicular stomatitis virus and bat adenovirus replication in cell lines from two bat species, M. davidii and Rhinolophus sinicus. We provide the first in vitro evidence of IFNβ antiviral activity in microbats, which has important implications for virus interactions with these hosts.     

Ecdysone-like metabolites, 14α-hydroxypinnasterols,from the red alga Laurencia pinnata

Four steroids with moulting hormone activity were isolated from Laurencia pinnata. These steroids are related structurally to β-ecdysone.     

Purification and identification of apophycocyanin α and β subunits from soluble protein extracts of the red algaCyanidium caldarium. Light exposure is not a prerequisite for biosynthesis of the protein moiety of this photosynthetic accessory pigment

Much controversy exists as to the level at which light exerts control over the biosynthesis of the photosynthetic apparatus in higher plants and other organisms. The eukaryotic red algaCyanidium caldarium, like higher plants, undergoes light induction of chlorophyll synthesis. In addition to chlorophyll the alga also synthesises the linear tetrapyrrole phycocyanobilin, which is combined with or apobiliproteins to form phycocyanin, the major light-harvesting pigment in this organism. We have previously shown that the tetrapyrrole precursor 5-aminolaevulinic acid (ALA) can substitute for light in inducing the biosynthesis of the phycocyanobilin moiety of this protein. We have also described the appearance of a protein of similar isoelectric point and molecular weight to phycocyanin in ALA-fed cells (Turner et al., 1992, Plant Physiol Biochem 30: 309–314). We now report on the protein's immunological and sequence identity with phycocyanin and subunits, and provide further evidence that bilin-apoprotein ligation is light dependent.     

Evolution of the Integrin α and β Protein Families

A phylogenetic analysis of vertebrate and invertebrate α integrins supported the hypothesis that two major families of vertebrate α integrins originated prior to the divergence of deuterostomes and protostomes. These two families include, respectively, the αPS1 and αPS2 integrins of Drosophila melanogaster, and each family has duplicated repeatedly in vertebrates but not in Drosophila. In contrast, a third family (including αPS3) has duplicated in Drosophila but is absent from vertebrates. Vertebrate αPS1 and αPS2 family members are found on human chromosomes 2, 12, and 17. Linkage of these family members may have been conserved since prior to the origin of vertebrates, and the two genes duplicated simultaneously. A phylogenetic analysis of β integrins did not clearly resolve whether vertebrate β integrin genes duplicated prior to the origin of vertebrates, although it suggested that at least the gene encoding vertebrate β4 may have done so. In general, the phylogeny of neither α nor β integrins showed a close correspondence with patterns of α–β heterodimer formation or other functional characteristics. One major exception to this trend involved αL, αM, αX, and αD, a monophyletic group of immune cell-expressed α integrins, which share a number of common functional characteristics and have evolved in coordinated fashion with their β integrin partners. Received: 22 June 2000 / Accepted: 11 September 2000