Structural research on surface layers: a focus on stability, surface layer homology domains, and surface layer-cell wall interactions.
Surface layers (S-layers) from Bacteria and Archaea are built from protein molecules arrayed in a two-dimensional lattice, forming the outermost cell wall layer in many prokaryotes. In almost half a century of S-layer research a wealth of structural, biochemical, and genetic data have accumulated, but it has not been possible to correlate sequence data with the tertiary structure of S-layer proteins to date. In this paper, some highlights of structural aspects of archaeal and bacterial S-layers that allow us to draw some conclusions on molecular properties are reviewed. We focus on the structural requirements for the extraordinary stability of many S-layer proteins, the structural and functional aspects of the S-layer homology domain found in S-layers, extracellular enzymes and related functional proteins, and outer membrane proteins, and the molecular interactions of S-layer proteins with other cell wall components. Finally, the perspectives and requirements for structural research on S-layers, which indicate that the investigation of isolated protein domains will be a prerequisite for solving S-layer structures at atomic resolution, are discussed.
Max-Planck-Institut für Biochemie, Abteilung Molekulare Strukturbiologie, Martinsried, D-82152, Germany.
H
H
Engelhardt
J
J
Peters
D000595:Amino Acid Sequence; D001105:Archaea / Q000648:ultrastructure*; D019843:Archaeal Proteins / Q000737:chemistry* / Q000648:ultrastructure*; D001419:Bacteria / Q000648:ultrastructure*; D001425:Bacterial Outer Membrane Proteins / Q000737:chemistry / Q000648:ultrastructure; D001426:Bacterial Proteins / Q000737:chemistry* / Q000648:ultrastructure*; D002462:Cell Membrane / Q000502:physiology* / Q000648:ultrastructure*; D002473:Cell Wall / Q000502:physiology* / Q000648:ultrastructure*; D008958:Models, Molecular; D008969:Molecular Sequence Data; D017434:Protein Structure, Tertiary; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid
D019843:Archaeal Proteins; D001425:Bacterial Outer Membrane Proteins; D001426:Bacterial Proteins