Related Experiment Video
Updated: Mar 19, 2026

Sedimentation Equilibrium of a Small Oligomer-forming Membrane Protein: Effect of Histidine Protonation on Pentameric Stability
Published on: April 2, 2015
Solvation driven conformational transitions in the second transmembrane domain of mycobacteriophage holin
Muralikrishna Lella1, Radhakrishnan Mahalakshmi1
1Molecular Biophysics Laboratory, Department of Biological Sciences, Indian Institute of Science Education and Research, Bhopal, 462023, India.
Abstract:
Holins are pore-forming membrane proteins synthesized by lytic phages. The second transmembrane domain (TM2) of Mycobacteriophage D29 holin presents an Ala- and Gly-rich sequence, with a currently unknown structure and function. In this study, we present the spectroscopic characterization of synthetic TM2 in various solvents, detergents, and lipids. We find that TM2 adopts α-helical conformation under conditions that promote intra-strand hydrogen bonding, such as organic solvents and detergent micelles. When we transfer the peptide to a well-hydrated environment, a polyproline II-like structure is obtained. Surprisingly, we find that the polyproline II-like conformation is retained in lipid vesicles. Based on our results, we present a putative role for TM2 in the process of pore formation by holin. © 2016 The Authors. Peptide Science Published by Wiley Periodicals, Inc. Biopolymers (Pept Sci) 108: 1-10, 2017.
Related Concept Videos
Molecular Chaperones and Protein Folding
The...
Mechanisms of Membrane Domain Formation
Another mechanism for membrane domain formation involves membrane proteins interacting with...
Energy to Drive Translocation
Generally, polypeptides are unfolded by two distinct...
Protein Folding
Protein Folding
Protein Structure Is Critical to Its Biological Function
Proteins perform a wide range of biological functions such as catalyzing chemical reactions, providing...
Cooperative Allosteric Transitions

