Structural study of porcine pancreatic elastase complexed with 7-amino-3-(2-bromoethoxy)-4-chloroisocoumarin as a nonreactivatable doubly covalent enzyme-inhibitor complex.Vijayalakshmi, J., Meyer Jr., E.F., Kam, C.M., Powers, J.C.
(1991) Biochemistry 30: 2175-2183
- PubMed: 1998677
- DOI: 10.1021/bi00222a022
- Primary Citation of Related Structures:
- PubMed Abstract:
- Effect of the 7-Amino Substituent on the Inhibitory Potency of Mechanism-Based Isocoumarin Inhibitors for Porcine Pancreatic and Human Neutrophil Elastases: A 1.85-Angstroms X-Ray Structure of the Complex between Porcine Pancreatic Elastase and 7-[(N-Tosylphenylalanyl)Amino]-4-Chloro-3-Methoxyisocoumarin
Hernandez, M.A., Powers, J.C., Glinski, J., Oleksyszyn, J., Vijayalakshmi, J., Meyerjunior, E.F.
(1992) J Med Chem 35: 1121
- Reaction of Porcine Pancreatic Elastase with 7-Substituted 3-Alkoxy-4-Chloroisocoumarins: Design of Potent Inhibitors Using the Crystal Structure of the Complex Formed with 4-Chloro-3-Ethoxy-7-Guanidino-Isocoumarin
Powers, J.C., Oleksyszyn, J., Narasimhan, S.L., Kam, C.-M., Radhakrishnan, R., Meyerjunior, E.F.
(1990) Biochemistry 29: 3108
- The 2.2-Angstrom Resolution X-Ray Crystal Structure of the Complex of Trypsin Inhibited by 4-Chloro-3-Ethoxy-7-Guanidinoisocoumarin: A Proposed Model of the Thrombin-Inhibitor Complex
Chow, M.M., Meyerjunior, E.F., Bode, W., Kam, C.-M., Radhakrishnan, R., Vijayalakshmi, J., Powers, J.C.
(1990) J Am Chem Soc 112: 7783
- Human Leukocyte and Porcine Pancreatic Elastase: X-Ray Crystal Structures, Mechanism, Substrate Specificity, and Mechanism-Based Inhibitors
Bode, W., Meyerjunior, E.F., Powers, J.C.
(1989) Biochemistry 28: 1951
- Crystal Structures of the Complex of Porcine Pancreatic Elastase with Two Valine-Derived Benzoxazinone Inhibitors
Radhakrishnan, R., Presta, L.G., Meyerjunior, E.F., Wildonger, R.
(1987) J Mol Biol 198: 417
- Stereospecific Reaction of 3-Methoxy-4-Chloro-7-Amino-Isocoumarin with Crystalline Porcine Pancreatic Elastase
Meyerjunior, E.F., Presta, L.G., Radhakrishnan, R.
(1985) J Am Chem Soc 107: 4091
The complex of porcine pancreatic elastase (PPE) with 7-amino-3-(2-bromoethoxy)-4-chloroisocoumarin, a potent mechanism-based inhibitor, was crystallized and the crystal structure determined at 1.9-A resolution with a final R factor of 17.1%. The unbiased difference Fourier electron density map showed continuous density from O gamma of Ser 195 to the benzoyl carbonyl carbon atom and from N epsilon 2 of His 57 to the carbon atom at the 4-position of the isocoumarin ring in the inhibitor ...
The complex of porcine pancreatic elastase (PPE) with 7-amino-3-(2-bromoethoxy)-4-chloroisocoumarin, a potent mechanism-based inhibitor, was crystallized and the crystal structure determined at 1.9-A resolution with a final R factor of 17.1%. The unbiased difference Fourier electron density map showed continuous density from O gamma of Ser 195 to the benzoyl carbonyl carbon atom and from N epsilon 2 of His 57 to the carbon atom at the 4-position of the isocoumarin ring in the inhibitor. This suggested unambiguously that the inhibitor was doubly covalently bound to the enzyme. It represents the first structural evidence for irreversible binding of an isocoumarin inhibitor to PPE through both Ser 195 and His 57 in the active site. The PPE-inhibitor complex is only partially activated in solution by hydroxylamine and confirms the existence of the doubly covalently bound complex along with the acyl enzyme. The benzoyl carbonyl oxygen atom of the inhibitor is not situated in the oxyanion hole formed by the amide (greater than NH) groups of Gly 193 and Ser 195. The complex is stabilized by the hydrogen-bonding interactions in the active site (from the N epsilon 2 of Gln 192 to the bromine atom in the inhibitor and the amino group at the 7-position of the isocoumarin ring to the carbonyl oxygen of Thr 41) and by van der Waals interactions. The inhibition rates of several 7-substituted 4-chloro-3-(bromoalkoxy)isocoumarins toward PPE were measured.(ABSTRACT TRUNCATED AT 250 WORDS)
Department of Bichemistry and Biophysics, Texas A&M University, College Station 77843-2128.