Crystal structure of the biologically active form of class Ib ribonucleotide reductase small subunit from Mycobacterium tuberculosis.
Two nrdF genes of Mycobacterium tuberculosis code for different R2 subunits of the class Ib ribonucleotide reductase (RNR). The proteins are denoted R2F-1 and R2F-2 having 71% sequence identity. The R2F-2 subunit forms the biologically active RNR complex with the catalytic R1E-subunit. We present the structure of the reduced R2F-2 subunit to 2.2 A resolution. Comparison of the R2F-2 structure with a model of R2F-1 suggests that the important differences are located at the C-terminus. We found that within class Ib, the E-helix close to the iron diiron centre has two preferred conformations, which cannot be explained by the redox-state of the diiron centre. In the R2F-2 structure, we also could see a mobility of alphaE in between the two conformations.
Uppsten
Malin
M
Department of Molecular Biology, Swedish University of Agricultural Sciences, Uppsala Biomedical Center, P.O. Box 590, SE-751 24 Uppsala, Sweden.
Davis
Jamaine
J
Rubin
Harvey
H
Uhlin
Ulla
U
D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000737:chemistry / Q000378:metabolism; D018360:Crystallography, X-Ray / Q000379:methods; D008958:Models, Molecular; D009169:Mycobacterium tuberculosis / Q000201:enzymology*; D011487:Protein Conformation; D017433:Protein Structure, Secondary; D021122:Protein Subunits / Q000737:chemistry; D012264:Ribonucleotide Reductases / Q000737:chemistry* / Q000378:metabolism
D001426:Bacterial Proteins; D021122:Protein Subunits; C114872:NrdF protein, bacteria; D012264:Ribonucleotide Reductases