Systematic variation in amino acid compositions of grass caryopses

Variation in amino acid patterns of 121 species (72 genera) of grass caryopses is extensively consistent with taxonomic groupings. The patterns of pooids and chloridoids are distinguishable from one another and from those of eu-panicoids and andropogonoids; the bamboos, Oryza, Stipeae, Ehrharta and Microlaena, which share certain morphological and anatomical features, also share a characteristic amino acid profile, while profiles of danthonoioids, Triodia and Aristida are clearly non-pooid. Caryopsis amino acid patterns vary independently of photosynthetic pathway. Embryos from taxonomically diverse genera all show very similar amino acid profiles, which differ strikingly from those of the endosperms, and the amino acid patterns of whole caryopses are dominated by their endosperms, which are responsible for the taxonomic variation. ‘Chemical scores’ of the caryopsis proteins, but not total protein contents, correlate to some extent with taxonomic groupings.     

Analysis of transmembrane proteins from eukaryotic cells

The topography and properties of plasma membrane proteins from mouse L-929 cells are studied by comparing their availability for enzymatic labeling on the external and internal surfaces of the membrane. In order to study the internal surface, phagolysosomes are prepared from cells after they ingest latex particles. The plasma membrane surrounding these seems to have an “inside-out” orientation. The sugars of the membrane glycoproteins in intact phagolysosomes are not available for interaction with lectins or available for periodate-borotritide labeling. A comparison of the lectin-binding proteins lableled by lactoperoxidase-catalyzed iodination on the external cell surface with those labeled on the internal cell surface suggests that a variety of plasma membrane glycoproteins span the lipid bilayer. Using two-dimensional gel electrophoresis it has been shown that selected proteins are labeled at both the internal and external faces of the plasma membrane. Analysis of the 2-D gel electrophoregrams reveals that there are two distinct prominent proteins at 60,000 and 100,000 daltons which are enzymatically iodinated from both sides of the membrane. The partial hydrolysis of the 100,000 dalton protein reveals that different peptides are iodinated when the iodination is performed on intact cells or on the phagolysosomes. These proteins are extensively phosphorylated in cells incubated with inorganic ³²P. We conclude that the phagolysosome is probably oriented in an “inside-out” configuration and that this membrane preparation can be used to study the topographic organization of membrane proteins. The use of oriented membranes, selective labeling of proteins, and affinity separation of proteins in combination with gel electrophoresis to define the position and properties of proteins is discussed.     

Synthesis and degradation of proteins during wheat endosperm development

Synthesis of proteins rich in lysine declines progressively with endosperm development and these proteins appear to be degraded preferentially at later stages. The proteolytic enzymes in extracts of endosperms at a late stage of development release considerably more lysine radioactivity from labelled endosperm proteins as compared with the enzymes in endosperms at an early stage.     

G4-quadruplex-binding proteins: review and insights into selectivity

There are over 700,000 putative G4-quadruplexes (G4Qs) in the human genome, found largely in promoter regions, telomeres, and other regions of high regulation. Growing evidence links their presence to functionality in various cellular processes, where cellular proteins interact with them, either stabilizing and/or anchoring upon them, or unwinding them to allow a process to proceed. Interest in understanding and manipulating the plethora of processes regulated by these G4Qs has spawned a new area of small-molecule binder development, with attempts to mimic and block the associated G4-binding protein (G4BP). Despite the growing interest and focus on these G4Qs, there is limited data (in particular, high-resolution structural information), on the nature of these G4Q-G4BP interactions and what makes a G4BP selective to certain G4Qs, if in fact they are at all. This review summarizes the current literature on G4BPs with regards to their interactions with G4Qs, providing groupings for binding mode, drawing conclusions around commonalities and highlighting information on specific interactions where available.     

Plasmodial heat shock proteins: targets for chemotherapy

Heat shock proteins act as molecular chaperones, facilitating protein folding in cells of living organisms. Their role is particularly important in parasites because environmental changes associated with their life cycles place a strain on protein homoeostasis. Not surprisingly, some heat shock proteins are essential for the survival of the most virulent malaria parasite, Plasmodium falciparum . This justifies the need for a greater understanding of the specific roles and regulation of malarial heat shock proteins. Furthermore, heat shock proteins play a major role during invasion of the host by the parasite and mediate in malaria pathogenesis. The identification and development of inhibitor compounds of heat shock proteins has recently attracted attention. This is important, given the fact that traditional antimalarial drugs are increasingly failing, as a consequence of parasite increasing drug resistance. Heat shock protein 90 (Hsp90), Hsp70/Hsp40 partnerships and small heat shock proteins are major malaria drug targets. This review examines the structural and functional features of these proteins that render them ideal drug targets and the challenges of targeting these proteins towards malaria drug design. The major antimalarial compounds that have been used to inhibit heat shock proteins include the antibiotic, geldanamycin, deoxyspergualin and pyrimidinones. The proposed mechanisms of action of these molecules and the pathways they inhibit are discussed.     

Recent Advances in Understanding Proteins Involved in Lipid Droplet Formation,Growth and Fusion

Lipid droplets （LDs） were once viewed as simple, inert lipid micelles. However, they are now known to be organelles with a rich proteome involved in a myriad of cellular processes. LDs are heterogeneous in nature with different sizes and compositions of phospholipids, neutral lipids and proteins. This review takes a focused look at the roles of proteins involved in the regulation of LD formation, expansion, and morphology. The related proteins are summarized such as the fat-specific protein （Fsp27）, fat storage-inducing trans- membrane （FIT） proteins, seipin and ADP-ribosylation factor 1-coat protein complex I （Arf-COPI）. Finally, we present important challenges in LD biology for a deeper understanding of this dynamic organelle to be achieved.     

Immunity of the greater wax moth Galleria mellonella

Investigation of insect immune mechanisms provides important information concerning innate immunity, which in many aspects is conserved in animals. This is one of the reasons why insects serve as model organisms to study virulence mechanisms of human pathogens. From the evolutionary point of view, we also learn a lot about host–pathogen interaction and adaptation of organisms to conditions of life. Additionally, insect‐derived antibacterial and antifungal peptides and proteins are considered for their potential to be applied as alternatives to antibiotics. While Drosophila melanogaster is used to study the genetic aspect of insect immunity, Galleria mellonella serves as a good model for biochemical research. Given the size of the insect, it is possible to obtain easily hemolymph and other tissues as a source of many immune‐relevant polypeptides. This review article summarizes our knowledge concerning G. mellonella immunity. The best‐characterized immune‐related proteins and peptides are recalled and their short characteristic is given. Some other proteins identified at the mRNA level are also mentioned. The infectious routes used by Galleria natural pathogens such as Bacillus thuringiensis and Beauveria bassiana are also described in the context of host–pathogen interaction. Finally, the plasticity of G. mellonella immune response influenced by abiotic and biotic factors is described.     

Multiple gene action determining a mouse salivary protein phenotype: Identification of the structural gene for androgen binding protein (Abp)

A novel variation in electrophoretic phenotype is described for a mouse salivary androgen binding protein (Abp). Crosses show that the variation is inherited in an autosomal codominant manner and protein characterization studies show that the variant Abp differs in isoelectric point from the common form of the protein. Those observations suggest that the variation involves the structural gene for the mouse salivary Abp. The genetic studies also show that the electrophoretic mobility of the variant Abp can be influenced by the sex-limited saliva pattern (Ssp) gene. The Ssp ^S allele alters the electrophoretic mobility of Abp in males at puberty or in females which have received exogenous testosterone [Karn, R. C., Dlouhy, S. R., Springer, K. R., Hjorth, J. P., and Nielsen, J. T. (1982). Biochem Genet. 20:493]. This study shows that Abp and Ssp are distinct genes which are not closely linked and that Ssp ^S is trans active in F₁ (Abp ^a /Abp ^b , Ssp ^S /Ssp ^F ) males.SRD was supported in part by PHS General Medical Training Grant T32 GMO7468 and the Indiana University School of Medicine Research Program in Academic Medicine. RCK was supported in part by PHS Career Development Award 1 KO4 AMOO284.     

Thermal effects in stretching of Go-like models of titin and secondary structures

The effect of temperature on mechanical unfolding of proteins is studied using a Go-like model with a realistic contact map and Lennard-Jones contact interactions. The behavior of the I27 domain of titin and its serial repeats is contrasted to that of simple secondary structures. In all cases, thermal fluctuations accelerate the unraveling process, decreasing the unfolding force nearly linearly at low temperatures. However, differences in bonding geometry lead to different sensitivity to temperature and different changes in the unfolding pattern. Due to its special native-state geometry, titin is much more thermally and elastically stable than the secondary structures. At low temperatures, serial repeats of titin show a parallel unfolding of all domains to an intermediate state, followed by serial unfolding of the domains. At high temperatures, all domains unfold simultaneously, and the unfolding distance decreases monotonically with the contact order, that is, the sequence distance between the amino acids that form the native contact.