1SBN

REFINED CRYSTAL STRUCTURES OF SUBTILISIN NOVO IN COMPLEX WITH WILD-TYPE AND TWO MUTANT EGLINS. COMPARISON WITH OTHER SERINE PROTEINASE INHIBITOR COMPLEXES

Summary for 1SBN

• Entry DOI: 10.2210/pdb1sbn/pdb
• Descriptor: SUBTILISIN NOVO BPN', EGLIN C, CALCIUM ION, ... (4 entities in total)
• Functional Keywords: complex(proteinase-inhibitor), complex(proteinase-inhibitor) complex, complex(proteinase/inhibitor)
• Biological source: Bacillus subtilis; More
• Cellular location: Secreted: P00782
• Total number of polymer chains: 2
• Total formula weight: 35775.74

Authors

Gruetter, M.G.,Heinz, D.W.,Priestle, J.P. (deposition date: 1991-12-20, release date: 1994-01-31, Last modification date: 2024-02-14)

Primary citation

Heinz, D.W.,Priestle, J.P.,Rahuel, J.,Wilson, K.S.,Grutter, M.G.
Refined crystal structures of subtilisin novo in complex with wild-type and two mutant eglins. Comparison with other serine proteinase inhibitor complexes.
J.Mol.Biol., 217:353-371, 1991

PubMed Abstract: 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.

PubMed: 1992167
DOI: 10.1016/0022-2836(91)90549-L

Experimental method

X-RAY DIFFRACTION (2.1 Å)