1sib
From Proteopedia
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| , resolution 2.4Å | |||||||
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| Ligands: | |||||||
| Activity: | Subtilisin, with EC number 3.4.21.62 | ||||||
| Resources: | FirstGlance, OCA, PDBsum, RCSB | ||||||
| Coordinates: | save as pdb, mmCIF, xml | ||||||
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. 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
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