1LD6
STRUCTURE OF BPTI_8A MUTANT
Summary for 1LD6
| Entry DOI | 10.2210/pdb1ld6/pdb |
| NMR Information | BMRB: 5375 |
| Descriptor | PANCREATIC TRYPSIN INHIBITOR (1 entity in total) |
| Functional Keywords | bpti, kunitz fold, hydrolase inhibitor |
| Biological source | Bos taurus (cattle) |
| Cellular location | Secreted: P00974 |
| Total number of polymer chains | 1 |
| Total formula weight | 6211.06 |
| Authors | Cierpicki, T.,Otlewski, J. (deposition date: 2002-04-08, release date: 2002-09-11, Last modification date: 2024-11-06) |
| Primary citation | Cierpicki, T.,Otlewski, J. NMR structures of two variants of bovine pancreatic trypsin inhibitor (BPTI) reveal unexpected influence of mutations on protein structure and stability. J.Mol.Biol., 321:647-658, 2002 Cited by PubMed Abstract: Here we determined NMR solution structures of two mutants of bovine pancreatic trypsin inhibitor (BPTI) to reveal structural reasons of their decreased thermodynamic stability. A point mutation, A16V, in the solvent-exposed loop destabilizes the protein by 20 degrees C, in contrast to marginal destabilization observed for G, S, R, L or W mutants. In the second mutant introduction of eight alanine residues at proteinase-contacting sites (residues 11, 13, 17, 18, 19, 34, 37 and 39) provides a protein that denatures at a temperature about 30 degrees C higher than expected from additive behavior of individual mutations. In order to efficiently determine structures of these variants, we applied a procedure that allows us to share data between regions unaffected by mutation(s). NOAH/DYANA and CNS programs were used for a rapid assignment of NOESY cross-peaks, structure calculations and refinement. The solution structure of the A16V mutant reveals no conformational change within the molecule, but shows close contacts between V16, I18 and G36/G37. Thus, the observed 4.3kcal/mol decrease of stability results from a strained local conformation of these residues caused by introduction of a beta-branched Val side-chain. Contrary to the A16V mutation, introduction of eight alanine residues produces significant conformational changes, manifested in over a 9A shift of the Y35 side-chain. This structural rearrangement provides about 6kcal/mol non-additive stabilization energy, compared to the mutant in which G37 and R39 are not mutated to alanine residues. PubMed: 12206780DOI: 10.1016/S0022-2836(02)00620-4 PDB entries with the same primary citation |
| Experimental method | SOLUTION NMR |
Structure validation
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