1TRQ

X-RAY CRYSTALLOGRAPHIC AND CALORIMERIC STUDIES OF THE EFFECTS OF THE MUTATION TRP 59 TYR IN RIBONUCLEASE T1

Summary for 1TRQ

• Entry DOI: 10.2210/pdb1trq/pdb
• Descriptor: RIBONUCLEASE T1 ISOZYME, CALCIUM ION, GUANOSINE-2'-MONOPHOSPHATE, ... (4 entities in total)
• Functional Keywords: hydrolase(endoribonuclease)
• Biological source: Aspergillus oryzae
• Total number of polymer chains: 2
• Total formula weight: 22949.91

Authors

Schubert, W.-D.,Saenger, W. (deposition date: 1993-07-06, release date: 1994-04-30, Last modification date: 2024-10-23)

Primary citation

Schubert, W.D.,Schluckebier, G.,Backmann, J.,Granzin, J.,Kisker, C.,Choe, H.W.,Hahn, U.,Pfeil, W.,Saenger, W.
X-ray crystallographic and calorimetric studies of the effects of the mutation Trp59-->Tyr in ribonuclease T1.
Eur.J.Biochem., 220:527-534, 1994

PubMed Abstract: 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.

PubMed: 8125111
DOI: 10.1111/j.1432-1033.1994.tb18652.x

Experimental method

X-RAY DIFFRACTION (2.3 Å)