Toward New Designed Proteins Derived from Bovine Pancreatic
Trypsin Inhibitor (BPTI): Covalent Cross-Linking of Two ‘Core
Modules' by Oxime-Forming Ligation
Natàlia Carulla
Clare Woodward
George Barany
10.1021/bc015518m.s001
https://acs.figshare.com/articles/journal_contribution/Toward_New_Designed_Proteins_Derived_from_Bovine_Pancreatic_Trypsin_Inhibitor_BPTI_Covalent_Cross-Linking_of_Two_Core_Modules_by_Oxime-Forming_Ligation/3584028
A 25-residue disulfide-cross-linked peptide, termed ‘oxidized core module' (OxCM), that includes
essentially all of the secondary structural elements of bovine pancreatic trypsin inhibitor (BPTI) most
refractory to hydrogen exchange, was shown previously to favor nativelike β-sheet structure [Carulla,
N., Woodward, C., and Barany, G. (2000) Synthesis and Characterization of a β-Hairpin Peptide That
Represents a ‘Core Module' of Bovine Pancreatic Trypsin Inhibitor (BPTI). <i>Biochemistry</i> <i>39</i>, 7927−7937]. The present work prepares to explore the hypothesis that the energies of nativelike
conformations, relative to other possible conformations, could be decreased further by covalent linkage
of two OxCMs. Optimized syntheses of six ∼50-residue OxCM dimers are reported herein, featuring
appropriate monomer modifications followed by oxime-forming ligation chemistry to create covalent
cross-links at various positions and with differing lengths. Several side reactions were recognized
through this work, and modified procedures to lessen or mitigate their occurrence were developed.
Particularly noteworthy, guanidine or urea denaturants that were included as peptide-solubilizing
components for some reaction mixtures were proven to form adducts with glyoxylyl moieties, thus
affecting rates and outcomes. All six synthetic OxCM dimers were characterized by 1D <sup>1</sup>H NMR;
three of them showed considerable chemical shift dispersion suggestive of self-association and mutual
stabilization between the monomer units.
2001-08-31 00:00:00
nativelike conformations
BPTI
OxCM dimers
Proteins Derived
residue
urea denaturants
core module
chemical shift dispersion
1 D 1 H NMR
glyoxylyl moieties
Core
hydrogen exchange
form adducts
Bovine Pancreatic Trypsin Inhibitor
reaction mixtures
Optimized syntheses
Biochemistry 39
covalent linkage
monomer units
Several side reactions
monomer modifications
Module
pancreatic trypsin inhibitor