Cysteine 265 Is in the Active Site of, But Is Not Essential for Catalysis by tRNA-Guanine Transglycosylase (TGT) from Escherichia coli
dc.contributor.author | Garcia, George A. | en_US |
dc.contributor.author | Chong, Shaorong | en_US |
dc.date.accessioned | 2006-09-11T15:39:06Z | |
dc.date.available | 2006-09-11T15:39:06Z | |
dc.date.issued | 1997-01 | en_US |
dc.identifier.citation | Garcia, George A.; Chong, Shaorong; (1997). "Cysteine 265 Is in the Active Site of, But Is Not Essential for Catalysis by tRNA-Guanine Transglycosylase (TGT) from Escherichia coli ." Journal of Protein Chemistry 16(1): 11-17. <http://hdl.handle.net/2027.42/45082> | en_US |
dc.identifier.issn | 0277-8033 | en_US |
dc.identifier.issn | 1573-4943 | en_US |
dc.identifier.uri | https://hdl.handle.net/2027.42/45082 | |
dc.identifier.uri | http://www.ncbi.nlm.nih.gov/sites/entrez?cmd=retrieve&db=pubmed&list_uids=9055203&dopt=citation | en_US |
dc.description.abstract | Site-directed mutagenesis and X-ray absorption spectroscopy studies have previously shown that the tRNA-guanine transglycosylase (TGT) from Escherichia coli is a zinc metalloprotein and identified the enzymic ligands to the zinc [Chong et al. (1995), Biochemistry 34, 3694–3701; Garcia et al. (1966), Biochemistry 35, 3133–3139]. During these studies one mutant, TGT (C265A), was found to exhibit a significantly lower specific activity, but was not found to be involved in the zinc site. The present report demonstrates that TGT is inactivated by treatment with thiol reagents ( e.g., DTNB, MMTS, and N-ethylmaleimide). Further, this inactivation is shown to be due to modification of cysteine 265. The kinetic parameters for the mutants TGT (C265A) and TGT (C265S), however, suggest that this residue is not performing a critical role in the TGT reaction. We conclude that cysteine 265 is in the active site of TGT, but is not performing a critical catalytic function. This conclusion is supported by the recent determination of the X-ray crystal structure of the TGT from Zymomonas mobilis [Romier et al. (1966), EMBO J. 15, 2850–2857], which reveals that the residue corresponding to cysteine 265 is distant from the putative catalytic site, but is in the middle of a region of the enzyme surface proposed to bind tRNA. | en_US |
dc.format.extent | 1287629 bytes | |
dc.format.extent | 3115 bytes | |
dc.format.mimetype | application/pdf | |
dc.format.mimetype | text/plain | |
dc.language.iso | en_US | |
dc.publisher | Kluwer Academic Publishers-Plenum Publishers; Plenum Publishing Corporation ; Springer Science+Business Media | en_US |
dc.subject.other | Bioorganic Chemistry | en_US |
dc.subject.other | Cysteine | en_US |
dc.subject.other | Animal Anatomy / Morphology / Histology | en_US |
dc.subject.other | Chemistry | en_US |
dc.subject.other | Organic Chemistry | en_US |
dc.subject.other | Biochemistry, General | en_US |
dc.subject.other | Queuine | en_US |
dc.subject.other | TRNA Modification | en_US |
dc.subject.other | Chemical Modification | en_US |
dc.subject.other | Mutagenesis | en_US |
dc.title | Cysteine 265 Is in the Active Site of, But Is Not Essential for Catalysis by tRNA-Guanine Transglycosylase (TGT) from Escherichia coli | en_US |
dc.type | Article | en_US |
dc.subject.hlbsecondlevel | Natural Resources and Environment | en_US |
dc.subject.hlbsecondlevel | Molecular, Cellular and Developmental Biology | en_US |
dc.subject.hlbsecondlevel | Ecology and Evolutionary Biology | en_US |
dc.subject.hlbtoplevel | Health Sciences | en_US |
dc.subject.hlbtoplevel | Science | en_US |
dc.description.peerreviewed | Peer Reviewed | en_US |
dc.contributor.affiliationum | Interdepartmental Program in Medicinal Chemistry, College of Pharmacy, University of Michigan, Ann Arbor, Michigan, 48109-1065, USA | en_US |
dc.contributor.affiliationother | New England Biolabs, Beverly, Massachusetts, 01915-5599, USA | en_US |
dc.contributor.affiliationumcampus | Ann Arbor | en_US |
dc.identifier.pmid | 9055203 | en_US |
dc.description.bitstreamurl | http://deepblue.lib.umich.edu/bitstream/2027.42/45082/1/10930_2004_Article_425322.pdf | en_US |
dc.identifier.doi | http://dx.doi.org/10.1023/A:1026334726357 | en_US |
dc.identifier.source | Journal of Protein Chemistry | en_US |
dc.owningcollname | Interdisciplinary and Peer-Reviewed |
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