Conformation of 2'GMP bound to a mutant ribonuclease T1 (Y45W) determined by X-ray diffraction and NMR methods.
The crystal structure of a mutant ribonuclease T1 (Y45W) complexed with a specific inhibitor, 2'GMP, has been determined by X-ray diffraction and refined at 1.9 A resolution to a conventional R-factor of 0.164. The mode of recognition of the guanine base by the enzyme is similar to that found for the wild-type ribonuclease T1 complexed with 2'GMP. The binding of the guanine base is clearly enhanced by maximum overlapping of the indole ring of Trp45 and the base. The glycosyl torsion angle of the inhibitor is in the syn conformation and the sugar exhibits a C3'-endo type pucker, which differs from that observed in the crystal of the complex between the wild-type ribonuclease T1 and 2'GMP. Analysis of 500-MHZ NMR spectra has also indicated that the 2'GMP molecule as bound to the mutant enzyme in solution exhibits a C3'-endo type pucker, similar to that bound to the wild-type enzyme in solution [Inagaki, Shimada, & Miyazawa (1985) Biochemistry 24, 1013-1020].
Itoh
T
T
Faculty of Pharmaceutical Sciences, Osaka University.
Tomita
K
K
Hakoshima
T
T
Hiroaki
H
H
Uesugi
S
S
Nishikawa
S
S
Amisaki
T
T
Morioka
H
H
Ohtsuka
E
E
Ikehara
M
M
D002236:Carbohydrate Conformation; D004926:Escherichia coli / Q000235:genetics; D006157:Guanosine Monophosphate / Q000737:chemistry*; D006860:Hydrogen Bonding; D009682:Magnetic Resonance Spectroscopy; D009154:Mutation; D011485:Protein Binding; D011487:Protein Conformation; D006163:Ribonuclease T1 / Q000737:chemistry* / Q000235:genetics; D012996:Solutions; D013237:Stereoisomerism; D014961:X-Ray Diffraction
D012996:Solutions; C026693:2'-guanylic acid; D006157:Guanosine Monophosphate; D006163:Ribonuclease T1