PDBsum entry 1w9a

Oxidoreductase

PDB id: 1w9a

Contents

Protein chains

142 a.a.

Waters ×371

References listed in PDB file

Key reference

Title

Crystal structure of the conserved hypothetical protein rv1155 from mycobacterium tuberculosis.

Authors

S.Canaan, G.Sulzenbacher, V.Roig-Zamboni, L.Scappuccini-Calvo, F.Frassinetti, D.Maurin, C.Cambillau, Y.Bourne.

Ref.

FEBS Lett, 2005, 579, 215-221. [DOI no: 10.1016/j.febslet.2004.11.069]

PubMed id

15620716

Abstract

With the aim of elucidating the biological function of hypothetical proteins unique amongst the Actynomyces sub-group of bacteria, we have solved the crystal structure of the conserved hypothetical protein Rv1155 from Mycobacterium tuberculosis at 1.8 A resolution. Rv1155 is a homodimer both in the crystal structure and in solution and folds into two separate domains consisting of a six-stranded anti-parallel beta-barrel fold flanked by two alpha-helices and a helix-turn-helix domain. Both domains contribute to the formation of two deep clefts at the dimer interface. The overall fold of Rv1155 strikingly resembles that of flavin mononucleotide-binding protein and pyridoxamine 5'-phosphate oxydase, but the architecture of the putative binding pocket is markedly different, consistent with the lack of color of Rv1155 and its inability to bind FMN. Rv1155 thus appears to belong to a group of proteins with stringent conservation of the binding cleft, having evolved towards a new binding function.

Figure 1.
Fig. 1. Overall fold of Rv1155. (A) Ribbon diagram of the dimer viewed along the approximate twofold axis with domain 1 from the two subunits shown in cyan and yellow, while the two domains 2 are shown in green. The β4–β5 loop and the C-terminal region are shown in orange. The secondary structure elements are indicated. (B) View oriented 90° from (a) and colored as in (a) showing the large cleft at the dimer interface through a transparent molecular surface in the left subunit.

Figure 2.
Fig. 2. Structural comparison. (A) Ribbon diagram of the D. vulgaris FMN-bp (Accession No. 1AXJ) with bound FMN (magenta) showing a single conformer (model 1) out of 20 and oriented and colored as the left subunit in Fig. 1A. (B) Ribbon diagram of the S. cerevisiae PNPOx dimer (Accession No. 1CI0) with bound FMN (magenta) with the central β-sheet of the left subunit oriented and colored as in Fig. 1A. The additional regions in PNPOx compared to Rv1155 and FMN-bp are shown in red, while those that significantly differ between Rv1155, FMN-bp and PNPOx are indicated in orange. In the left subunit, the FMN-binding site at the dimer interface is shown through a transparent molecular surface.

The above figures are reprinted by permission from the Federation of European Biochemical Societies: FEBS Lett (2005, 579, 215-221) copyright 2005.