1EKB
THE SERINE PROTEASE DOMAIN OF ENTEROPEPTIDASE BOUND TO INHIBITOR VAL-ASP-ASP-ASP-ASP-LYS-CHLOROMETHANE
Summary for 1EKB
| Entry DOI | 10.2210/pdb1ekb/pdb |
| Descriptor | ENTEROPEPTIDASE, VAL-ASP-ASP-ASP-ASP-LYK PEPTIDE, ZINC ION, ... (5 entities in total) |
| Functional Keywords | enteropeptidase, trypsinogen activation, hydrolase-hydrolase inhibitor complex, hydrolase/hydrolase inhibitor |
| Biological source | Bos taurus (cattle) More |
| Cellular location | Membrane; Single-pass type II membrane protein (Probable): P98072 P98072 |
| Total number of polymer chains | 3 |
| Total formula weight | 28574.47 |
| Authors | Fuetterer, K.,Lu, D.,Sadler, J.E.,Waksman, G. (deposition date: 1999-05-02, release date: 1999-10-14, Last modification date: 2024-11-06) |
| Primary citation | Lu, D.,Futterer, K.,Korolev, S.,Zheng, X.,Tan, K.,Waksman, G.,Sadler, J.E. Crystal structure of enteropeptidase light chain complexed with an analog of the trypsinogen activation peptide. J.Mol.Biol., 292:361-373, 1999 Cited by PubMed Abstract: Enteropeptidase is a membrane-bound serine protease that initiates the activation of pancreatic hydrolases by cleaving and activating trypsinogen. The enzyme is remarkably specific and cleaves after lysine residues of peptidyl substrates that resemble trypsinogen activation peptides such as Val-(Asp)4-Lys. To characterize the determinants of substrate specificity, we solved the crystal structure of the bovine enteropeptidase catalytic domain to 2.3 A resolution in complex with the inhibitor Val-(Asp)4-Lys-chloromethane. The catalytic mechanism and contacts with lysine at substrate position P1 are conserved with other trypsin-like serine proteases. However, the aspartyl residues at positions P2-P4 of the inhibitor interact with the enzyme surface mainly through salt bridges with the Nzeta atom of Lys99. Mutation of Lys99 to Ala, or acetylation with acetic anhydride, specifically prevented the cleavage of trypsinogen or Gly-(Asp)4-Lys-beta-naphthylamide and reduced the rate of inhibition by Val-(Asp)4-Lys-chloromethane 22 to 90-fold. For these reactions, Lys99 was calculated to account for 1.8 to 2.5 kcal mol(-1) of the free energy of transition state binding. Thus, a unique basic exosite on the enteropeptidase surface has evolved to facilitate the cleavage of its physiological substrate, trypsinogen. PubMed: 10493881DOI: 10.1006/jmbi.1999.3089 PDB entries with the same primary citation |
| Experimental method | X-RAY DIFFRACTION (2.3 Å) |
Structure validation
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