Conformational studies of human des-trp/sup 1/,Nle/sup 12/-minigastrin in water-trifluoroethanol mixtures by /sup 1/H NMR and circular dichroism

Journal Article · Tue Feb 23 04:00:00 EST 1988 · Biochemistry; (United States)

OSTI ID:5408717

Mammi, S; Mammi, N J; Peggion, E

The /sup 1/H NMR spectrum of the title peptide, H-Leu-(Glu)/sub 5/-Ala-Tyr-Gly-Trp-Nle-Asp-Phe-NH/sub 2/, in 90% H/sub 2/O/10% D/sub 2/O was assigned by two-dimensional methods, and the displacement of the proton resonances upon addition of 2,2,2-trifluoroethanol (TFE) was followed. This permitted the assignment of the spectrum in 90% TFE/10% D/sub 2/O. While the water conformation of the minigastrin analog is random, the CD spectrum indicates that an ordered structure is present in TFE. Variable-temperature NMR data in this medium show that six amide protons have low temperature coefficients, two of the five Glu's, Trp, Nle, Asp, and Phe. These results were interpreted in terms of an ..cap alpha..-helical stretch comprising the Leu and the five Glu residues and a 3/sub 10/-helix initiated by a ..beta..-turn at the sequence -Ala-Tyr-Gly-Trp-. Both CD and NMR data at different solvent compositions show two regions of conformational change, between 20 and 25% water and above 60% water.

• Research Organization: Univ. of Padova, Via Marzolo (Italy)
• OSTI ID: 5408717
• Journal Information: Biochemistry; (United States), Journal Name: Biochemistry; (United States) Vol. 27:4; ISSN BICHA
• Country of Publication: United States
• Language: English

Related Subjects

550601* -- Medicine-- Unsealed Radionuclides in Diagnostics
62 RADIOLOGY AND NUCLEAR MEDICINE
BARYONS
CHEMICAL SHIFT
CONFORMATIONAL CHANGES
DICHROISM
ELEMENTARY PARTICLES
FERMIONS
GASTRIN
HADRONS
HEAVY WATER
HORMONES
HYDROGEN COMPOUNDS
MAGNETIC CIRCULAR DICHROISM
MAGNETIC RESONANCE
NUCLEAR MAGNETIC RESONANCE
NUCLEONS
ORGANIC COMPOUNDS
OXYGEN COMPOUNDS
PEPTIDE HORMONES
PEPTIDES
POLYPEPTIDES
PROTEINS
PROTONS
RESONANCE
WATER