1sib
From Proteopedia
|
REFINED CRYSTAL STRUCTURES OF SUBTILISIN NOVO IN COMPLEX WITH WILD-TYPE AND TWO MUTANT EGLINS. COMPARISON WITH OTHER SERINE PROTEINASE INHIBITOR COMPLEXES
Overview
The crystal structures of the complexes formed between subtilisin Novo and three inhibitors, eglin c, Arg45-eglin c and Lys53-eglin c have been determined using molecular replacement and difference Fourier techniques and refined at 2.4 A, 2.1 A, and 2.4 A resolution, respectively. The mutants Arg45-eglin c and Lys53-eglin c were constructed by site-directed mutagenesis in order to investigate the inhibitory specificity and stability of eglin c. Arg45-eglin became a potent trypsin inhibitor, in contrast to native eglin, which is an elastase inhibitor. This specificity change was rationalized by comparing the structures of Arg45-eglin and basic pancreatic trypsin inhibitor and their interactions with trypsin. The residue Arg53, which participates in a complex network of hydrogen bonds formed between the core and the binding loop of eglin c, was replaced with the shorter basic amino acid lysine in the mutant Lys53-eglin. Two hydrogen bonds with Thr44, located in the binding loop, can no longer be formed but are partially restored by a water molecule bound in the vicinity of Lys53. Eglin c in complexes with both subtilisin Novo and subtilisin Carlsberg was crystallized in two different space groups. Comparison of the complexes showed a rigid body rotation for the eglin c core of 11.5 degrees with respect to the enzyme, probably caused by different intermolecular contacts in both crystal forms.
About this Structure
1SIB is a Protein complex structure of sequences from Bacillus subtilis and Hirudo medicinalis with as ligand. Active as Subtilisin, with EC number 3.4.21.62 Full crystallographic information is available from OCA.
Reference
Refined crystal structures of subtilisin novo in complex with wild-type and two mutant eglins. Comparison with other serine proteinase inhibitor complexes., Heinz DW, Priestle JP, Rahuel J, Wilson KS, Grutter MG, J Mol Biol. 1991 Jan 20;217(2):353-71. PMID:1992167
Page seeded by OCA on Thu Feb 21 15:01:50 2008
