Solvation driven conformational transitions in the second transmembrane domain of mycobacteriophage holin.
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.
Molecular Biophysics Laboratory, Department of Biological Sciences, Indian Institute of Science Education and Research, Bhopal, 462023, India.
Muralikrishna
M
Lella
Molecular Biophysics Laboratory, Department of Biological Sciences, Indian Institute of Science Education and Research, Bhopal, 462023, India.
Radhakrishnan
R
Mahalakshmi
D000595:Amino Acid Sequence; D002942:Circular Dichroism; D006860:Hydrogen Bonding; D006863:Hydrogen-Ion Concentration; D008823:Micelles; D008969:Molecular Sequence Data; D009160:Mycobacteriophages / Q000378:metabolism*; D010455:Peptides / Q000138:chemical synthesis / Q000737:chemistry; D058849:Protein Refolding; D017433:Protein Structure, Secondary; D012997:Solvents / Q000737:chemistry*; D014764:Viral Proteins / Q000737:chemistry* / Q000378:metabolism; D014867:Water / Q000737:chemistry
D008823:Micelles; D010455:Peptides; D012997:Solvents; D014764:Viral Proteins; D014867:Water
Mycobacteriophage holin; circular dichroism spectroscopy; peptide helices; polyproline II structure; transmembrane peptide