Crystal structure of the apo forms of psi 55 tRNA pseudouridine synthase from Mycobacterium tuberculosis: a hinge at the base of the catalytic cleft

The three-dimensional structure of the RNA-modifying enzyme, psi55 tRNA pseudouridine synthase from Mycobacterium tuberculosis, is reported. The 1.9-A resolution crystal structure reveals the enzyme, free of substrate, in two distinct conformations. The structure depicts an interesting mode of prote...

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Bibliographic Details
Published in:The Journal of biological chemistry 2004-06, Vol.279 (23), p.24585-24591
Main Authors: Chaudhuri, Barnali N, Chan, Sum, Perry, L Jeanne, Yeates, Todd O
Format: Article
Language:English
Subjects:
Binding Sites
Catalytic Domain
Cloning, Molecular
Crystallography, X-Ray
Intramolecular Lyases - chemistry
Intramolecular Transferases
Models, Biological
Models, Molecular
Mycobacterium tuberculosis
Mycobacterium tuberculosis - enzymology
Protein Binding
Protein Conformation
Protein Structure, Secondary
RNA - chemistry
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Summary:The three-dimensional structure of the RNA-modifying enzyme, psi55 tRNA pseudouridine synthase from Mycobacterium tuberculosis, is reported. The 1.9-A resolution crystal structure reveals the enzyme, free of substrate, in two distinct conformations. The structure depicts an interesting mode of protein flexibility involving a hinged bending in the central beta-sheet of the catalytic module. Key parts of the active site cleft are also found to be disordered in the substrate-free form of the enzyme. The hinge bending appears to act as a clamp to position the substrate. Our structural data furthers the previously proposed mechanism of tRNA recognition. The present crystal structure emphasizes the significant role that protein dynamics must play in tRNA recognition, base flipping, and modification.
ISSN:0021-9258
1083-351X
DOI:10.1074/jbc.M401045200