Bacterial Membranes: Structural and Molecular Biology
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Membranes are pivotal components of life, acting as formidable insulators that demarcate a living cell; generate energy in the form of ion gradients; transport ions, proteins, nucleic acids, nutrients, and metabolites; and provide transduction systems to sense the environment and to communicate with other cells. Membranes also provide shape and structure to cells and are important in cell motility. In addition, they fulfill a scaffolding function for proteins and organelles that interact with the extracellular environment. Written by specialists in the field, this book provides a comprehensive overview of the structural and molecular biology of cellular processes that occur at or near bacterial membranes. The book presents and discusses recent progress on the function and involvement of membranes in bacterial physiology, enabling a greater understanding of the molecular details of the cell envelope, its biogenesis, and its function. The topics covered include: cell wall growth * shape and division * the outer membrane of Gram-negative bacteria * outer membrane protein biosynthesis * bacterial lipoproteins * mycobacteria * lipid composition * ABC transporters * transport across the outer membrane * drug passage across membranes * bacterial membrane proteins * secretion systems * signal transduction * signalling mechanisms * bacterial membranes in adhesion and pathogenesis * membranes as a drug target. This cutting-edge text will provide a valuable resource for all those working in this field and is recommended for all microbiology libraries.
Rv2262c in combination with Rv2261c function as apolipoprotein N-acyl transferases, and whether or not they have the same specificity as Ppm1 (Rv2051c). Bacterial Lipoproteins | 153 Lipoprotein biosynthesis and virulence Lipoproteins have been shown to play a direct role in the interaction of bacterial pathogens with their hosts (Kovacs-Simon et al., 2011). The virulence-related functions of lipoproteins include colonization, invasion, evasion of host defence, and immunomodulation.
(HExxH). Both M. smegmatis and M. tuberculosis lpqM (Rv0419) restore DNA transfer. Secretion and lipidation of LpqM are mandatory for complementation of the phenotype. Expression of functional LpqM in the donor strain is sufficient for proficient transfer (Nguyen et al., 2009). So far, a substrate of LpqM has not been identified. LpqY(Rv1235)-SugA-SugB-SugC operon Five putative carbon uptake permeases are encoded in the genome of M. tuberculosis. Of these, LpqY-SugA-SugB-SugC encodes an ABC
linkage unit (Vollmer, 2008). By contrast, the type III capsule polysaccharide of Streptococcus agalactiae is linked to GlcNAc residues. The mechanism of attachment of these secondary cell wall polymers to PG in Gram-positive bacteria and the enzymes catalysing the attachment reactions are largely unknown. The peptides in peptidoglycan The peptides are amide-linked to the lactoyl group of MurNAc and contain amino acids that are not present in proteins, such as d-alanine, d-glutamic acid and
involved in the Type I secretion pathway that allows the export of proteins without the use of the SecYEG translocon at the IM. TolC forms a unique trimer structure, with three protomers contributing four strands each to form a single 12-stranded β-barrel (Fig. 3.3). In addition Outer Membrane Protein Biosynthesis | 95 Table 3.1 List of currently reviewed Escherichia coli OMPs in the UniProt database Protein Length in amino acids Proposed function/category Evidence as BAM UniProt ID
gave important insights and possible mechanisms of OMP folding into lipid bilayers, how the β-barrel maturation process takes place inside cells remained uncertain until genetics and protein–protein interaction studies identified the BAM complex and its components as the OMP assembly factors. The BAM complex catalyses the essential function of OMP folding and membrane insertion, and newly emerging data are starting to reveal the structure and mechanism of the BAM complex. So what do the currently