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A Dynamic C‐Terminal Segment in the Mycobacterium tuberculosis Mn/Fe R2lox Protein Can Adopt a Helical Structure with Possible Functional Consequences
Author(s) -
Andersson Charlotta S.,
Berthold Catrine L.,
Högbom Martin
Publication year - 2012
Publication title -
chemistry and biodiversity
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.427
H-Index - 70
eISSN - 1612-1880
pISSN - 1612-1872
DOI - 10.1002/cbdv.201100428
Subject(s) - chemistry , ribonucleotide reductase , ligand (biochemistry) , crystallography , mycobacterium tuberculosis , protein structure , stereochemistry , biophysics , biochemistry , biology , tuberculosis , medicine , receptor , pathology , protein subunit , gene
Mycobacterium tuberculosis R2‐like ligand‐binding oxidase (MtR2lox) belongs to a recently discovered group of proteins that are homologous to the ribonucleotide reductase R2 proteins. MtR2lox carries a heterodinuclear Mn/Fe cofactor and, unlike R2 proteins, a large ligand‐binding cavity. A unique tyrosine‐valine cross link is also found in the vicinity of the active site. To date, all known structures of R2 and R2lox proteins show a disordered C‐terminal segment. Here, we present two new crystal forms of MtR2lox, revealing an ordered helical C‐terminal. The ability of alternating between an ordered and disordered state agrees well with bioinformatic analysis of the protein sequence. Interestingly, ordering of the C‐terminal helix shields a large positively charged patch on the protein surface, potentially used for interaction with other cellular components. We hypothesize that the dynamic C‐terminal segment may be involved in control of protein function in vivo.