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 00:00:00 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), Vol. 27:4
• Country of Publication: United States
• Language: English

Related Subjects

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