𝔖 Bobbio Scriptorium
✦   LIBER   ✦

Conformation of malformin A: A proton magnetic resonance and a circular dichroism study

✍ Scribed by Marius Ptak

Publisher
Wiley (John Wiley & Sons)
Year
1973
Tongue
English
Weight
785 KB
Volume
12
Category
Article
ISSN
0006-3525

No coin nor oath required. For personal study only.

✦ Synopsis

Abstract

Malformin A is a cyclic pentapeptide with an intramolecular disulfide bridge. The conformation in solution of this molecule has been studied by NMR and CD. The 270 MHz Proton spectrum in dimethyl sulfoxide is well resolved and the peaks corresponding to the five residues have been assigned.

From the temperature dependence of chemical shifts of the peptide protons and from the exchange rate of these protons, it is concluded that the NH proton of one Cys is shielded from the solvent. This observation and HN~α~CH angles, estimated from the corresponding coupling constants, a proposed conformation of the peptide backbone. From the H~β~C~α~CH coupling constants, a P chirality for the disulfide bridge is proposed. Such a conformation is confirmed by the circular dichroism spectrum which shows a negative band at λ > 250 nm.

It is concluded that the conformation of malformin A is rigid and that the disulfide bridge is exposed to interact with biological receptors.

📜 SIMILAR VOLUMES

Circular dichroism and proton magnetic r
Circular dichroism and proton magnetic resonance studies of random chain poly-L-lysine
✍ Richard M. Epand; Graham E. Wheeler; Mario A. Moscarello 📂 Article 📅 1974 🏛 Wiley (John Wiley & Sons) 🌐 English ⚖ 427 KB 👁 1 views

## Abstract The 218‐nm peak, characteristic of the circular dichroism of randomly coiled poly‐α‐amino acids can be demonstrated in solutions of penta‐L‐lysine, α‐glycyl‐L‐lysine, as well as poly‐L‐lysine. The thermal stability of the particular state that gives rise to this 218‐nm band in the CD is

The conformation of malformin A
The conformation of malformin A
✍ David Hall; Paul John Lyons; Nicola Pavitt; John A. Trezise 📂 Article 📅 1982 🏛 John Wiley and Sons 🌐 English ⚖ 496 KB

## Abstract The conformation of the cyclic pentapeptide malformin A has been deduced by systematically generating possible models for the molecule, and minimizing the conformation energy of each. Only one of the low‐energy solutions is fully consistent with the reported CD and NMR spectra, and this

Conformational aspects of gastrin-relate
Conformational aspects of gastrin-related peptides: A circular dichroism study
✍ E. Peggion; E. Jaeger; S. Knof; L. Moroder; E. Wuensch 📂 Article 📅 1981 🏛 Wiley (John Wiley & Sons) 🌐 English ⚖ 952 KB

## Abstract The conformational properties of a series of gastrin‐related peptides in aqueous solution and in 2,2,2‐trifluoroethanol (TFE) have been investigated by CD measurements. In aqueous solution the peptides Leu^32^‐HG‐34 (human big gastrin), Nle^15^‐HG‐17 (human little gastrin), and Nle^11^‐

A proton magnetic resonance study of iso
A proton magnetic resonance study of isomeric alkylidencyanoesters
✍ Ernest Giralt; Francisco López; Mercedes Alvarez 📂 Article 📅 1975 🏛 John Wiley and Sons 🌐 English ⚖ 260 KB

## Abstract Ethyl 2‐cyano‐3‐methyl‐4‐phenyl‐2‐pentenoate was obtained as a mixture of two geometric isomers. An aromatic solvent induced shift experiment and calculations of the difference in the chemical shifts of methyl protons linked to the double bond lead to the assignation of the geometry of

Conformation and circular dichroism of D
Conformation and circular dichroism of DNA
✍ Cindy A. Sprecher; Walter A. Baase; W. Curtis Johnson Jr. 📂 Article 📅 1979 🏛 Wiley (John Wiley & Sons) 🌐 English ⚖ 496 KB 👁 2 views

## Abstract CD spectra of calf thymus, __C. perfringens, E. coli__, and __M. luteus__ DNA have been measured in the vacuum‐uv region to about 168 nm for the A‐, B‐, and C‐forms. The positive band at about 187 nm and the negative band at about 170 nm found for each type and form of DNA are sensitive

Circular dichroism of polynucleotides: D
Circular dichroism of polynucleotides: Dimers as a function of conformation
✍ W. C. Johnson Jr.; M. S. Itzkowitz; I. Tinoco JR. 📂 Article 📅 1972 🏛 Wiley (John Wiley & Sons) 🌐 English ⚖ 567 KB

Working within the restrictions of a model, we have calculated the circular dichroism of the dinucleoside phosphates ApA, CpC, ApC, and CpA for various conformations. Comparing the calculated curves with those measured in aqueous solution we find agreement for ( 1 ) ApA as a right-handed helix with