Synthetic peptide models for the redox-active disulfide loop of glutaredoxin. Conformational studies

Journal Article · Tue Apr 05 00:00:00 EDT 1988 · Biochemistry; (United States)

DOI:https://doi.org/10.1021/bi00407a032· OSTI ID:5173204

Kishore, R; Raghothama, S; Balaram, P

Two cyclic peptide disulfides have been synthesized as models for the 14-membered redox-active disulfide loop glutaredoxin. /sup 1/H NMR studies at 270 MHz in chloroform solutions establish a type I ..beta..-turn conformation for the Pro-X segment in both peptides, stabilized by a 4 ..-->.. 1 hydrogen bond between the Cys(1) CO and Cys(4) NH groups. Nuclear Overhauser effects establish that the aromatic ring in the X = Phe peptide is oriented over the central peptide unit. In dimethyl sulfoxide solutions two conformational species are observed in slow exchange on the NMR time scale, for both peptides. These are assigned to type I and type II ..beta..-turn structures with -Pro-Tyr(Phe)-as the corner resides. The structural assignments are based on correlation of NMR parameters with model 14-membered cyclic cystine peptides with Pro-X spacers. Circular dichroism studies based on the -S-S-n-sigma* transition suggest a structural change in the disulfide bridge with changing solvent polarity, establishing conformational coupling between the peptide backbone and the disulfide linkage in these systems.

• Research Organization: Indian Institute of Science, Bangalore
• OSTI ID: 5173204
• Journal Information: Biochemistry; (United States), Vol. 27:7
• Country of Publication: United States
• Language: English

Related Subjects

62 RADIOLOGY AND NUCLEAR MEDICINE
PROTEINS
MOLECULAR STRUCTURE
NUCLEAR MAGNETIC RESONANCE
CONFORMATIONAL CHANGES
DICHROISM
PROTONS
REDOX REACTIONS
THIN-LAYER CHROMATOGRAPHY
BARYONS
CHEMICAL REACTIONS
CHROMATOGRAPHY
ELEMENTARY PARTICLES
FERMIONS
HADRONS
MAGNETIC RESONANCE
NUCLEONS
ORGANIC COMPOUNDS
RESONANCE
SEPARATION PROCESSES
550601* - Medicine- Unsealed Radionuclides in Diagnostics