Traditionally, Bacteria are divided according to their behaviour to the Gram staining. Bacteria that are stained by the Gram’s method are commonly referred to as Gram-positive, whereas others (that are not stained) are referred to as Gram negative. Gram-negative Bacteria include a number of important classes such as proteobacteria, cyanobacteria, spirochaetes, green sulfur and green non-sulfur bacteria. They all share a common structure in their surface which is composed of a cytoplasmic membrane, a periplasmic space and an outer membrane.
Published in Chapter:
Bacterial ß-Barrel Outer Membrane Proteins: A Common Structural Theme Implicated in a Wide Variety of Functional Roles
Pantelis G. Bagos (University of Central Greece, and University of Athens, Greece) and Stavros J. Hamodrakas (University of Athens, Greece)
Copyright: © 2009
|Pages: 26
DOI: 10.4018/978-1-60566-076-9.ch010
Abstract
ß-barrel outer membrane proteins constitute the second and less well-studied class of transmembrane proteins. They are present exclusively in the outer membrane of Gram-negative bacteria and presumably in the outer membrane of mitochondria and chloroplasts. During the last few years, remarkable advances have been made towards an understanding of their functional and structural features. It is now wellknown that ß-barrels are performing a large variety of biologically important functions for the bacterial cell. Such functions include acting as specific or non-specific channels, receptors for various compounds, enzymes, translocation channels, structural proteins, and adhesion proteins. All these functional roles are of great importance for the survival of the bacterial cell under various environmental conditions or for the pathogenic properties expressed by these organisms. This chapter reviews the currently available literature regarding the structure and function of bacterial outer membrane proteins. We emphasize the functional diversity expressed by a common structural motif such as the ß-barrel, and we provide evidence from the current literature for dozens of newly discovered families of transmembrane ß-barrels.