Structure-function correlations in antibacterial and cytolytic peptides: studies on Seminalplasmin : Seminalplasmin-derived and related synthetic peptides

Abstract

One of the important aspects of protein chemistry is to relate activity to structure or newlineestablish structure-function relationships. During the past fifteen years, several proteins and newlinepeptides that are potent antibacterial and/or cytolytic agents have been purified and sequenced newlinefrom various organisms all along the evolutionary scale. One of the structural motifs which has newlinebeen identified to be important for the biological activities of several of these newlineantibacterial/cytolytic peptides is either an amphiphilic a-helical or amphiphilic p-structure. newlineHowever, factors that determine the specificity of antibacterial and hemolytic activities are not newlinewell understood. newlineThe investigations described in this thesis have been directed towards understanding the newlinestructure-function correlations in seminalplasmin (SPLN), an antimicrobial peptide present newlinein bovine seminalplasma. newlineThe thesis is divided into seven Chapters and the contents of the Chapters are briefly newlineoutlined below. newlineIn the introductory chapter - Chapter1- some of the well studied antimicrobial and newlinehemolytic peptides are reviewed. Those peptides which are covered include antimicrobial newlinepeptides from phagocyte granules, amphibian skin, insects, horseshoe crabs and hemolytic newlinepeptides like melittin, mastoparan, bombolitins and 8-toxin. Earlier work on seminalplasmin newline(SPLN) is also reviewed in this Chapter. newlineChapter 2 is devoted to the determination of the sequence of SPLN as well as its newlinetheoretical analysis. This Chapter is divided into two Sections, A and B. Section A reviews the newlinecurrent methods used in protein sequencing as well as methodsused for predicting secondary newline(vi) newlinestructure from the sequence .. In Section B purification of SPLN by HPLC and its sequencing is newlinedescribed. The Section also describes the methods developed for separating and identifying PTH newlineamino acids which is a pre-requisite for any sequencing work.