1i2f
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(New page: 200px<br /><applet load="1i2f" size="450" color="white" frame="true" align="right" spinBox="true" caption="1i2f, resolution 1.95Å" /> '''Ribonuclease T1 V16A...)
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Revision as of 14:52, 20 November 2007
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Ribonuclease T1 V16A mutant, form II
Overview
Differential scanning calorimetry, urea denaturation, and X-ray, crystallography were combined to study the structural and energetic, consequences of refilling an engineered cavity in the hydrophobic core of, RNase T1 with CH(3), SH, and OH groups. Three valines that cluster, together in the major hydrophobic core of T1 were each replaced with Ala, Ser, Thr, and Cys. Compared to the wild-type protein, all these mutants, reduce the thermodynamic stability of the enzyme considerably. The, relative order of stability at all three positions is as follows: Val >, Ala approximately equal to Thr > Ser. The effect of introducing a, sulfhydryl group is more variable. Surprisingly, a Val --> Cys mutation in, a hydrophobic environment can be as or even more destabilizing than a Val, --> Ser mutation. Furthermore, our results reveal that the penalty for, introducing an OH group into a hydrophobic cavity is roughly the same as, the gain obtained from filling the cavity with a CH(3) group. The inverse, equivalence of the behavior of hydroxyl and methyl groups seems to be, crucial for the unique three-dimensional structure of the proteins. The, importance of negative design elements in this context is highlighted.
About this Structure
1I2F 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.
Reference
Hydrophobic core manipulations in ribonuclease T1., De Vos S, Backmann J, Prevost M, Steyaert J, Loris R, Biochemistry. 2001 Aug 28;40(34):10140-9. PMID:11513591
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