Structure and mechanism of ADP-ribose-1'-monophosphatase (Appr-1'-pase), a ubiquitous cellular processing enzyme |
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Authors: | Kumaran Desigan Eswaramoorthy Subramaniam Studier F William Swaminathan Subramanyam |
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Affiliation: | Biology Department, Brookhaven National Laboratory, Upton, NY 11973, USA. |
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Abstract: | Appr-1'-pase, an important and ubiquitous cellular processing enzyme involved in the tRNA splicing pathway, catalyzes the conversion of ADP-ribose-1'monophosphate (Appr-1'-p) to ADP-ribose. The structures of the native enzyme from the yeast and its complex with ADP-ribose were determined to 1.9 A and 2.05 A, respectively. Analysis of the three-dimensional structure of this protein, selected as a target in a structural genomics project, reveals its putative function and provides clues to the catalytic mechanism. The structure of the 284-amino acid protein shows a two-domain architecture consisting of a three-layer alphabetaalpha sandwich N-terminal domain connected to a small C-terminal helical domain. The structure of Appr-1'-pase in complex with the product, ADP-ribose, reveals an active-site water molecule poised for nucleophilic attack on the terminal phosphate group. Loop-region residues Asn 80, Asp 90, and His 145 may form a catalytic triad. |
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Keywords: | ADP-ribose-1″-monophosphate tRNA splicing pathway structural genomics X-ray structure |
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