title: Solution structure of Rv2377c-founding member of the MbtH-like protein family.
abstract: The Mycobacterium tuberculosis protein Rv2377c (71 residues, MW=8.4kDa) has been characterized using nuclear magnetic resonance (NMR) and circular dichroism (CD) spectroscopy. Rv2377c was the first identified member of the MbtH-like family of proteins. MbtH-like proteins have been implicated in siderophore biosynthesis, however, their precise biochemical function remain unknown. Size exclusion chromatography and NMR spectroscopy show that Rv2377c is a monomer in solution. Circular dichroism spectroscopy indicates that Rv2377c unfolds upon heating and will reversibly fold into its native conformation upon cooling. Using NMR-based methods the solution structure of Rv2377c was determined and some of the dynamic properties of the protein studied. The protein contains a three-strand, anti-parallel beta-sheet (beta3:beta1:beta2) nestled against one C-terminal alpha-helix (S44-N55). Weak or absent amide cross peaks in the (1)H-(15)N HSQC spectrum for many of the beta1 and beta2 residues suggest intermediate motion on the ms to mus time scale at the beta1:beta2 interface. Amide cross peaks in the (1)H-(15)N HSQC spectrum are absent for all but one residue at the C-terminus (W56-D71), a region that includes a highly conserved sequence WXDXR, suggesting this region is intrinsically disordered. The latter observation differs with the crystal structure of another MbtH-like protein, PA2412 from Pseudomonas aeruginosa, where a second ordered alpha-helix was observed at the extreme C-terminus.
authors.affiliation: Pacific Northwest National Laboratory, Richland, WA 99352, USA. garry.buchko@pnl.gov
authors.forename: Garry W
authors.initials: GW
authors.lastname: Buchko
authors.forename: Chang-Yub
authors.initials: CY
authors.lastname: Kim
authors.forename: Thomas C
authors.initials: TC
authors.lastname: Terwilliger
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Myler
mesh_terms: D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000235:genetics* / Q000502:physiology; D002942:Circular Dichroism; D017124:Conserved Sequence; D009682:Magnetic Resonance Spectroscopy / Q000379:methods; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009169:Mycobacterium tuberculosis / Q000235:genetics* / Q000378:metabolism; D017510:Protein Folding; D017433:Protein Structure, Secondary; D016415:Sequence Alignment; D017262:Siderophores; D013329:Structure-Activity Relationship
chemical_list: D001426:Bacterial Proteins; D017262:Siderophores