Protein internal flexibility and global stability: effect of urea on hydrogen exchange rates of bovine pancreatic trypsin inhibitor.


Abstract

The hydrogen isotope exchange kinetics of buried NH protons in bovine pancreatic trypsin inhibitor (BPTI) was measured in 8 M urea at 30 degrees C and pH 3.5. The data were analyzed by the two-process model in which slower exchanging protons utilize an unfolding mechanism and more rapidly exchanging protons exchange from the folded state. Urea accelerates the set of protons exchanging by the unfolding mechanism, all of which have approximately the same exchange rate constants in urea. For protons in this set, the ratio of exchange rate constants in the presence and absence of urea is used to estimate delta delta G(0-->8M urea) = 6.6 kcal/mol. For the set of protons exchanging from the folded state, 8 M urea either has no effect or slows exchange. Slowing of exchange by urea implies binding of urea to sites at or near the exchanging proton. Some buried protons exchanging from the folded state have diminished rates in 8 M urea, meaning that urea is accessible to these buried sites. Several unassigned side-chain NH's of arginine or lysine are highly protected from exchange by urea, suggesting that they are the location of urea binding sites on the surface of the molecule. Study holds ProTherm entries: 4548 Extra Details: hydrogen isotope exchange kinetics; unfolding mechanism;,buried protons; urea binding sites; surface

Submission Details

ID: niT8MPTL

Submitter: Connie Wang

Submission Date: April 24, 2018, 8:26 p.m.

Version: 1

Publication Details
Kim KS;Woodward C,Biochemistry (1993) Protein internal flexibility and global stability: effect of urea on hydrogen exchange rates of bovine pancreatic trypsin inhibitor. PMID:7690588
Additional Information

Structure view and single mutant data analysis

Study data

No weblogo for data of varying length.
Colors: D E R H K S T N Q A V I L M F Y W C G P
 

Data Distribution

Studies with similar sequences (approximate matches)

Correlation with other assays (exact sequence matches)


Relevant PDB Entries

Structure ID Release Date Resolution Structure Title
1T8M 2004-05-13T00:00:00+0000 1.8 CRYSTAL STRUCTURE OF THE P1 HIS BPTI MUTANT- BOVINE CHYMOTRYPSIN COMPLEX
1T8N 2004-05-13T00:00:00+0000 1.75 CRYSTAL STRUCTURE OF THE P1 THR BPTI MUTANT- BOVINE CHYMOTRYPSIN COMPLEX
1G6X 2000-11-08T00:00:00+0000 0.86 ULTRA HIGH RESOLUTION STRUCTURE OF BOVINE PANCREATIC TRYPSIN INHIBITOR (BPTI) MUTANT WITH ALTERED BINDING LOOP SEQUENCE
2TPI 1981-10-26T00:00:00+0000 2.1 ON THE DISORDERED ACTIVATION DOMAIN IN TRYPSINOGEN. CHEMICAL LABELLING AND LOW-TEMPERATURE CRYSTALLOGRAPHY
3OTJ 2010-09-12T00:00:00+0000 2.15 A Crystal Structure of Trypsin Complexed with BPTI (Bovine Pancreatic Trypsin Inhibitor) by X-ray/Neutron Joint Refinement
3TGK 1998-07-19T00:00:00+0000 1.7 TRYPSINOGEN MUTANT D194N AND DELETION OF ILE 16-VAL 17 COMPLEXED WITH BOVINE PANCREATIC TRYPSIN INHIBITOR (BPTI)
2R9P 2007-09-13T00:00:00+0000 1.4 Human mesotrypsin complexed with bovine pancreatic trypsin inhibitor(BPTI)
1K6U 2001-10-17T00:00:00+0000 1.0 Crystal Structure of Cyclic Bovine Pancreatic Trypsin Inhibitor
1JV9 2001-08-28T00:00:00+0000 0 NMR Structure of BPTI Mutant G37A
1JV8 2001-08-28T00:00:00+0000 0 NMR Structure of BPTI Mutant G37A

Relevant UniProtKB Entries

Percent Identity Matching Chains Protein Accession Entry Name
91.0 Pancreatic trypsin inhibitor P04815 BPT2_BOVIN
100.0 Pancreatic trypsin inhibitor P00974 BPT1_BOVIN
91.4 Pancreatic trypsin inhibitor P00975 IBPS_BOVIN