Assembly Instructions for Polypeptide Models: Academic Press/Molecular Design Inc. Precision Molecular Models

By Edward J. Barrett

Assembly Instructions for Polypeptide Models provides assembly procedures for? polypeptide chains and for modeling the ?-helix and the parallel and antiparallel ?-pleated sheets. This text is divided into nine chapters and starts with a brief introduction to the basic unit of polypeptide or protein structure, which is the amino acid. The subsequent chapters deal with the components of the model system, including the torsion angles and the asymmetric ?-carbon atom. The remaining chapters present specific instructions for the construction of free amino acids, polypeptide end groups, side chain groups, secondary structures, and side chain torsion angles. This book will prove useful to protein and peptide scientists, organic chemists, and biochemists.

• Language: English
• Publisher: Academic Press
• Release date: Jun 28, 2014
• ISBN: 9781483264417

Book preview

pieces.

1

THE PEPTIDE UNIT

Publisher Summary

This chapter discusses the structure of polypeptide. The basic unit of polypeptide or protein structure is the amino acid. Amino acids are carboxylic acids with an amino group attached to the carbon next to the carboxyl group. This carbon atom is called the 2 α-carbon. Amino acids form polypeptides when the amino group of one amino acid condenses with the carboxyl group of another amino acid to form an amide, or peptide linkage. The polypeptide backbone is comprised of a repeating –C–C–N– unit. That is, peptide linkages alternate with α-carbons. The polypeptides have an amino end or N-terminus and a carboxyl end or C-terminus. In many natural polypeptides, the peptide linkage is planar, that is, the torsion angle of the C–N bond is either 0° or 180°. Most commonly, the oxygen and hydrogen atoms of this linkage aretrans to one another (torsion angle is 180°). This is called the trans-peptide linkage. In the cis-peptide linkage the torsion angle is