1RGA

CRYSTAL STRUCTURE OF RNASE T1 WITH 3'-GMP AND GUANOSINE: A PRODUCT COMPLEX

Summary for 1RGA

• Entry DOI: 10.2210/pdb1rga/pdb
• Descriptor: RIBONUCLEASE T1, CALCIUM ION, GUANOSINE-3'-MONOPHOSPHATE, ... (5 entities in total)
• Functional Keywords: hydrolase(endoribonuclease)
• Biological source: Aspergillus oryzae
• Total number of polymer chains: 1
• Total formula weight: 11781.23

Authors

Zegers, I.,Wyns, L. (deposition date: 1993-06-07, release date: 1993-10-31, Last modification date: 2024-10-16)

Primary citation

Zegers, I.,Haikal, A.F.,Palmer, R.,Wyns, L.
Crystal structure of RNase T1 with 3'-guanylic acid and guanosine.
J.Biol.Chem., 269:127-133, 1994

PubMed Abstract: A modified method for the synthesis and separation of endo and exo guanosine 2',3'-cyclophosphorothioate (cGPS) has been developed. The exo diastereoisomer has been co-crystallized with RNase T1. cGPS is known to be a RNase T1 inhibitor but is also a very slow substrate. It was hydrolyzed during the crystallization, leaving 3'-guanylic acid (3'-GMP) in the active site. As a guanosine was also found to be bound in a subsite, the enzyme contains the products of the reaction of guanylyl-3',5'-guanosine. The structure was refined to a resolution of 1.7 A and yielded a final R value of 14.5%. In contrast to previous 3'-GMP complexes of RNase T1, the ribose phosphate moiety of the inhibitor is in contact with all the active site residues. The phosphate forms hydrogen bonds with Asn36, Tyr38, Arg77, His92, and with Asn49 from a symmetry-related molecule. The ribose 2'-OH is hydrogen-bonded to both Glu58 and His40. The interactions in the active site of the present structure are compared to those found in the 2'-GMP complex of RNase T1.

PubMed: 8276784

Experimental method

X-RAY DIFFRACTION (1.7 Å)