Molecular Orbital Calculations for Amino Acids and Peptides

This book is intended mainly for biochemists who would like to augment experimentalresearch in thedomainofaminoacids andsmallpeptideswith theoretical calculations at the ab initio level. The book does not require a profound knowledge of mathematics and quantum chemistry. It teaches one rather how to use computer software such as the Gaussian programs and gives examples of problems treated in this manner. Chapter 1 describes the calculations and one of the programs used for ab initio work. Chapter 2 describes calculations on small amino acids, such as glycine and alanine. Chapter3discusses the biochemical propertiesofGABA (gamma amino butyricacid),which isoneofthe most important amino acids ofthe nervous system.Ab initio calculations performed in order to study the structure of GABA are presented. Chapter 4 discusses an amino acid related to GABA, namely DABA (diaminobutyricacid),presentinginformation about itsstructureand trans port properties. A number of amino acids, essentials in the biochemistry of organisms, are discussed in Chapter 5. These acids have been subjected to ab initio investigation. Proline, a special amino acid as far as structure is concerned, is discussed in Chapter 6. Chapter7discusses two sulfur-containingamino acids,taurine and hypo taurine, presenting some experimental studies on their mode of action and an ab initio study of their structure. Startingwith Chapter8,small peptidesofgreat importancearediscussed. Glucagon, a small peptide that plays a role in diabetes, is the subject of Chapter 8. Chapter 9 discusses the pheromone alpha factor, from an experimental and theoretical point of view. Chapter 10 presents calculations on tight turns in proteins.