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| {{STRUCTURE_1rds| PDB=1rds | SCENE= }} | | {{STRUCTURE_1rds| PDB=1rds | SCENE= }} |
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| '''CRYSTAL STRUCTURE OF RIBONUCLEASE MS (AS RIBONUCLEASE T1 HOMOLOGUE) COMPLEXED WITH A GUANYLYL-3',5'-CYTIDINE ANALOGUE'''
| | ===CRYSTAL STRUCTURE OF RIBONUCLEASE MS (AS RIBONUCLEASE T1 HOMOLOGUE) COMPLEXED WITH A GUANYLYL-3',5'-CYTIDINE ANALOGUE=== |
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| ==Overview==
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| A ribonuclease T1 homologue, ribonuclease Ms (RNase Ms) from Aspergillus saitoi, has been crystallized as a complex with a substrate analogue GfpC where the 2'-hydroxyl (2'-OH) group of guanosine in guanylyl-3',5'-cytidine (GpC) is replaced by the 2'-fluorine (2'-F) atom to prevent transesterification. The crystal structure of the complex was solved at 1.8-A resolution to a final R-factor of 0.204. The role of His92 (RNase T1 numbering) as the general acid catalyst was confirmed. Of the two alternative candidates for a general base to abstract a proton from the 2'-OH group, His40 and Glu58 were found close to the 2'-F atom, making the decision between the two groups difficult. We then superposed the active site of the RNase Ms/GfpC complex with that of pancreatic ribonuclease S (RNase S) complexed with a substrate analogue UpcA, a phosphonate analogue of uridylyl-3',5'-adenosine (UpA), and found that His12 and His119 of RNase A almost exactly coincided with Glu58 and His92, respectively, of RNase Ms. Similar superposition with a prokaryotic microbial ribonuclease, RNase St [Nakamura, K. T., Iwahashi, K., Yamamoto, Y., Iitaka, Y., Yoshida, N., & Mitsui, Y. (1982) Nature 299, 564-566], also indicated Glu58 as a general base. Thus the present comparative geometrical studies consistently favor, albeit indirectly, the traditional as well as the most recent notion [Steyaert, J., Hallenga, K., Wyns, L., & Stanssens, P. (1990) Biochemistry 29, 9064-9072] that Glu58, rather than His40, must be the general base catalyst in the intact enzymes of the RNase T1 family.
| | The line below this paragraph, {{ABSTRACT_PUBMED_8218254}}, adds the Publication Abstract to the page |
| | (as it appears on PubMed at http://www.pubmed.gov), where 8218254 is the PubMed ID number. |
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| | {{ABSTRACT_PUBMED_8218254}} |
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| ==About this Structure== | | ==About this Structure== |
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| [[Category: Nakamura, K T.]] | | [[Category: Nakamura, K T.]] |
| [[Category: Nonaka, T.]] | | [[Category: Nonaka, T.]] |
| ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sat May 3 07:22:21 2008'' | | |
| | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Mon Jul 28 23:50:32 2008'' |