1trq
X-RAY CRYSTALLOGRAPHIC AND CALORIMERIC STUDIES OF THE EFFECTS OF THE MUTATION TRP 59 TYR IN RIBONUCLEASE T1
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OverviewOverview
Two mutants of ribonuclease T1 (RNaseT1), [59-tyrosine]ribonuclease T1, (W59Y) and [45-tryptophan,59-tyrosine]ribonuclease T1 (Y45W/W59Y) possess, between 150% and 190% wild-type activity. They have been crystallised as, complexes of the inhibitor 2'-guanylic acid and analysed by X-ray, diffraction at resolutions of 0.23 nm and 0.24 nm, respectively. The space, group for both is monoclinic, P2(1), with two molecules/asymmetric unit, W59Y: a = 4.934 nm, b = 4.820 nm, c = 4.025 nm, beta = 90.29 degrees., Y45W/W59Y: a = 4.915 nm, b = 4.815 nm, c = 4.015 nm, beta = 90.35 degrees., Compared to wild-type RNaseT1 in complex with 2'-guanylic acid (2'GMP), both mutant inhibitor complexes indicate that the replacement of Trp59 by, Tyr leads to a 0.04-nm inward shift of the single alpha-helix and to, significant differences in the active-site geometry, inhibitor, conformation and inhibitor binding. Calorimetric studies of a range of, mutants [24-tryptophan]ribonuclease T1 (Y24W), [42-tryptophan]ribonuclease, T1 (Y42W), [45-tryptophan]ribonuclease T1 (Y45W), [92-alanine]ribonuclease, T1 (H92A) and [92-threonine]ribonuclease T1 (H92T) with and without the, further mutation Trp59-->Tyr showed that mutant proteins for which Trp59, is replaced by Tyr exhibit slightly decreased thermal stability.
About this StructureAbout this Structure
1TRQ is a Single protein structure of sequence from Aspergillus oryzae with CA and 2GP as ligands. Active as Ribonuclease T(1), with EC number 3.1.27.3 Full crystallographic information is available from OCA.
ReferenceReference
X-ray crystallographic and calorimetric studies of the effects of the mutation Trp59-->Tyr in ribonuclease T1., Schubert WD, Schluckebier G, Backmann J, Granzin J, Kisker C, Choe HW, Hahn U, Pfeil W, Saenger W, Eur J Biochem. 1994 Mar 1;220(2):527-34. PMID:8125111
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