Metal ions modulate the plastic nature of Mycobacterium tuberculosis chaperonin-10.
Chaperonin-10s possess a highly flexible segment of approximately 10 residues that covers their dome-like structure and closes the central cavity of the chaperonin assembly. The dome loop is believed to contribute to the plasticity of their oligomeric structure. We have exploited the presence of a single tryptophan residue occurring in the dome loop of Mycobacterium tuberculosis chaperonin-10 (cpn-10), and through intrinsic fluorescence measurements show that in the absence of metal ions, the tryptophan is almost fully solvent exposed at neutral pH. The dome loop, however, assumes a closed conformation in the presence of metal ions, or at low pH. These changes are fully reversed in the presence of chelating agents such as EDTA, confirming the role of cations in modulating the metastable states of cpn-10.
Taneja
B
B
Institute of Microbial Technology, Sector 39-A, Chandigarh 160 036, India.
Mande
S C
SC
D000595:Amino Acid Sequence; D002412:Cations / Q000494:pharmacology; D018835:Chaperonin 10 / Q000737:chemistry* / Q000187:drug effects; D002614:Chelating Agents / Q000494:pharmacology; D019281:Dimerization; D006863:Hydrogen-Ion Concentration; D008670:Metals / Q000494:pharmacology*; D008969:Molecular Sequence Data; D009169:Mycobacterium tuberculosis / Q000737:chemistry; D018583:Pliability / Q000187:drug effects; D011487:Protein Conformation / Q000187:drug effects; D017434:Protein Structure, Tertiary / Q000187:drug effects; D016415:Sequence Alignment; D012997:Solvents / Q000378:metabolism; D013050:Spectrometry, Fluorescence; D014364:Tryptophan / Q000378:metabolism
D002412:Cations; D018835:Chaperonin 10; D002614:Chelating Agents; D008670:Metals; D012997:Solvents; D014364:Tryptophan