Taxonomic distribution of proteins containing G5 domains

The tree below includes only several representative species and genera. The complete taxonomic breakdown of all proteins containing G5 domains can be accessed here. Click the counts or percentage values to display the corresponding proteins.

Crystal structure of the resuscitation-promoting factor (DeltaDUF)RpfB from M.tuberculosis.

Ruggiero A, Tizzano B, Pedone E, Pedone C, Wilmanns M, Berisio R
J Mol Biol. 2009; 385: 153-62

Mycobacterium tuberculosis is able to establish a non-replicating state andsurvive in an intracellular habitat for years. Resuscitation of dormant M.tuberculosis bacteria is promoted by resuscitation-promoting factors (Rpfs),which are secreted from slowly replicating bacteria close to dormant bacteria.Here we report the crystal structure of a truncated form of RpfB (residues194-362), the sole indispensable Rpf of the five Rpfs encoded in this bacteriumgenome. The structure, denoted as (DeltaDUF)RpfB, exhibits a comma-like shapeformed by a lysozyme-like globular catalytic domain and an elongated G5 domain,which is widespread among cell surface binding proteins. The G5 domain, whosestructure was previously uncharacterised, presents some peculiar features. Thebasic structural motif of this domain, which represents the tail of thecomma-like structure, is a novel super-secondary-structure element, made of twobeta-sheets interconnected by a pseudo-triple helix. This intricate organisation leads to the exposure of several backbone hydrogen-bond donors/acceptors.Mutagenesis analyses and solution studies indicate that this protein construct aswell as the full-length form are elongated monomeric proteins. Although(DeltaDUF)RpfB does not self-associate, the exposure of structural elements(backbone H-bond donors/acceptors and hydrophobic side chains) that are usuallyburied in globular proteins is typically associated with adhesive properties.This suggests that the RpfB G5 domain has a cell-wall adhesive function, whichallows the catalytic domain to be properly oriented for the cleavage reaction.Interestingly, sequence comparisons indicate that these structural features arealso shared by G5 domains involved in biofilm formation.

The G5 domain: a potential N-acetylglucosamine recognition domain involved inbiofilm formation.

Bateman A, Holden MT, Yeats C
Bioinformatics. 2005; 21: 1301-3

SUMMARY: Biofilms are complex microbial communities found at surfaces that areoften associated with extracellular polysaccharides. Biofilm formation is acomplex process that is being understood at the molecular level only recently. Wehave identified a novel domain that we call the G5 domain (named after itsconserved glycine residues), which is found in a variety of enzymes such asStreptococcal IgA peptidases and various glycosyl hydrolases in bacteria. The G5 domain is found in the Accumulation Associated Protein (AAP), which is animportant component in biofilm formation in Staphylococcus aureus. A commonfeature of the proteins containing G5 domains is N-acetylglucosamine binding, andwe attribute this function to the G5 domain. CONTACT: agb@sanger.ac.uk.