title: Structural and biophysical characterization of Mycobacterium tuberculosis dodecin Rv1498A.
abstract: Dodecins (assembly of twelve monomers) are the smallest known flavoprotein with only 65-73 amino acids and are involved in binding and storage of flavins in archaea. Here we report the crystal structure of Rv1498A, a Mycobacterium tuberculosis dodecin. This bacterial dodecin structure is similar to that of other reported dodecins. Each monomer has a 3 stranded β-sheet and an α-helix perpendicular to it. This protein has polyextreme (halophilic and thermophilic) properties. Interestingly, positively and negatively charged residues aggregate separately and do not seem to contribute to thermophilic and halophilic stability. We have examined the interactions that stabilize the Rv1498A dodecamer by preparing selected point mutants that break salt bridges and hydrophobic contacts, thereby leading to collapse of the assembly.
authors.affiliation: Department of Biological Sciences, National University of Singapore, Singapore 117543, Singapore.
authors.forename: Fengxia
authors.initials: F
authors.lastname: Liu
authors.forename: Junhui
authors.initials: J
authors.lastname: Xiong
authors.forename: Sundaramurthy
authors.initials: S
authors.lastname: Kumar
authors.forename: Chunyan
authors.initials: C
authors.lastname: Yang
authors.forename: Shengxiang
authors.initials: S
authors.lastname: Ge
authors.forename: Shaowei
authors.initials: S
authors.lastname: Li
authors.forename: Ningshao
authors.initials: N
authors.lastname: Xia
authors.forename: Kunchithapadam
authors.initials: K
authors.lastname: Swaminathan
mesh_terms: D019943:Amino Acid Substitution; D001426:Bacterial Proteins / Q000737:chemistry* / Q000235:genetics; D018360:Crystallography, X-Ray; D005486:Flavin Mononucleotide / Q000737:chemistry; D005182:Flavin-Adenine Dinucleotide / Q000737:chemistry; D016297:Mutagenesis, Site-Directed; D009169:Mycobacterium tuberculosis / Q000737:chemistry*; D011485:Protein Binding; D055550:Protein Stability; D020836:Protein Structure, Quaternary; D017434:Protein Structure, Tertiary; D011994:Recombinant Proteins / Q000737:chemistry* / Q000235:genetics; D013499:Surface Properties
chemical_list: D001426:Bacterial Proteins; D011994:Recombinant Proteins; D005182:Flavin-Adenine Dinucleotide; D005486:Flavin Mononucleotide