Crystal Structure of the Resuscitation-Promoting Factor (Delta DUF)RpfB from M. tuberculosis(829 views) Ruggiero A, Tizzano B, Pedone E, Pedone C, Wilmanns M, Berisio R
Instituto di Biostrutture e Bioimmagini, CNR, Via Mezzocannone 16, I-80134 Naples, Italy
European Molecular Biology Laboratory, Hamburg, DESY, Notkestrasse 85, 22603 Hamburg, Germany
Dipartimento delle Scienze Biologiche, Sezione di Biostrutture, Università degli Studi di Napoli Federico II, I-80134 Naples, Italy
References: Not available.
Crystal Structure of the Resuscitation-Promoting Factor (Delta DUF)RpfB from M. tuberculosis
Mycobacterium tuberculosis is able to establish a non-replicating state and survive 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 (residues 194-362), the sole indispensable Rpf of the five Rpfs encoded in this bacterium genome. The structure, denoted as (Delta DUF) RpfB, exhibits a comma-like shape formed by a lysozyme-like globular catalytic domain and an elongated G5 domain, which is widespread among cell surface binding proteins. The G5 domain, whose structure was previously uncharacterised, presents some peculiar features. The basic structural motif of this domain, which represents the tail of the comma-like structure, is a novel super-secondary-structure element, made of two P-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 as wen as the full-length form are elongated monomeric proteins. Although (Delta DUF) RpfB does not self-associate, the exposure of structural elements (backbone H-bond donors/acceptors and hydrophobic side chains) that are usually buried in globular proteins is typically associated with adhesive properties. This suggests that the RpfB G5 domain has a cell-wall adhesive function, which allows the catalytic domain to be properly oriented for the cleavage reaction. Interestingly, sequence comparisons indicate that these structural features are also shared by G5 domains involved in biofilm formation. (C) 2008 Elsevier Ltd. All rights reserved
Crystal Structure of the Resuscitation-Promoting Factor (Delta DUF)RpfB from M. tuberculosis