𝔖 Bobbio Scriptorium
✦   LIBER   ✦

The solution conformation of malformin A

✍ Scribed by Alan E. Tonelli

Publisher
Wiley (John Wiley & Sons)
Year
1978
Tongue
English
Weight
269 KB
Volume
17
Category
Article
ISSN
0006-3525

No coin nor oath required. For personal study only.

✦ Synopsis

Abstract

Solution conformations of the cyclic pentapeptide plant‐hormone malformin A, whose conformational freedom is constrained by an intramolecular disulfide bridge, are derived and presented here. The nmr and CD data of Ptak are used to place restrictions on the search for possible malformin A solution conformers of low energy. Only two distinct conformers were found to be consistent with Ptak's data. Both structures are characterized by an internally buried (solvent‐shielded) D‐Cys^2^ amide proton, a seven‐membered (1–3)hydrogen bond between (N–H) and (OC), and a disulfide bridge conformation with a P chirality as manifested in the nmr study by the temperature independence of the amide proton chemical shifts for the D‐Cys^2^ and D‐Leu^4^ residues and the negative sign of the long wavelength maximum in the CD spectrum, respectively. Inspection of space‐filling molecular models of both structures indicates severe steric barriers to their rapid interconversion. Thus, it appears that only one of the two conformers may be present in solution. The difference in their calculated dipole moments (4.6 and 6.9__D__) suggests an experimental method for distinguishing between the two proposed solution structures.

📜 SIMILAR VOLUMES

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 flexibilities in malformi
Conformational flexibilities in malformin A
✍ Alok K. Mitra; R. Chandrasekaran 📂 Article 📅 2007 🏛 Wiley (John Wiley & Sons) 🌐 English ⚖ 783 KB

## Abstract The linked‐atom‐least‐squares (LALS) technique has been applied to generate exactly cyclized and stereochemically satisfactory conformations of the cyclic pentapeptide, malformin A, which contains an intramolecular disulfide bridge across a D‐Cys—D‐Cys linkage. Consistent with theoretic

Conformation of malformin A: A proton ma
Conformation of malformin A: A proton magnetic resonance and a circular dichroism study
✍ Marius Ptak 📂 Article 📅 1973 🏛 Wiley (John Wiley & Sons) 🌐 English ⚖ 785 KB

## 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 assig

The solution conformation of acarbose
The solution conformation of acarbose
✍ Klaus Bock; Henrik Pedersen 📂 Article 📅 1984 🏛 Elsevier Science 🌐 English ⚖ 388 KB

The pseudotetrasaccharide acarbose (1) is a potent inhibitor of glucosidases and saccharases in in vitro systems'%\*, and is of potential interest in connection with the regulation of the uptake of D-glUCOSe in the intestine. In order to obtain a better understanding of the inhibitory activity of 1,