1iyy
From Proteopedia
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NMR STRUCTURE OF Gln25-RIBONUCLEASE T1, 24 STRUCTURES
Overview
Ribonuclease (RNase) T1 is a guanyloribonuclease, having two isozymes in, nature, Gln25- and Lys25-RNase T1. Between these two isozymes, there is no, difference in catalytic activity and three-dimensional structure; however, Lys25-RNase T1 is slightly more stable than Gln25-RNase T1. Recently, it, has been suggested that the existence of a salt bridge between Lys25 and, Asp29/Glu31 in Lys25-RNase T1 contributes to the stability. To elucidate, the effects of the replacement of Lys25 with a Gln on the conformation and, microenvironments of RNase T1 in detail, the three-dimensional solution, structure of Gln25-RNase T1 was determined by simulated-annealing, calculations. As a result, the topology of the overall folding was shown, to be very similar to that of the Lys25-isozyme except for some, differences. In particular, there were two differences in the property of, torsion angles of the two disulfide bonds and the conformations of the, residues 11-13, 63-66, and 92-93. With regard to the residues 11-13, the, lack of the above-mentioned salt bridge in Gln25-RNase T1 was thought to, induce the conformational difference of this segment as compared with the, Lys25-isozyme. Furthermore, it was proposed that the perturbation of this, segment might transfer to the residues 92-93 via the two disulfide bonds.
About this Structure
1IYY is a Single protein structure of sequence from Aspergillus oryzae. Active as Ribonuclease T(1), with EC number 3.1.27.3 Full crystallographic information is available from OCA.
Reference
Determination of the NMR structure of Gln25-ribonuclease T1., Hatano K, Kojima M, Suzuki E, Tanokura M, Takahashi K, Biol Chem. 2003 Aug;384(8):1173-83. PMID:12974386
Page seeded by OCA on Tue Nov 20 17:47:22 2007
