Introduction to Peptide Science

Ian W. Hamley

• Éditeur: Wiley
• Année: 2020
• ISBN:
  9781119698197
• Édition: 1
• Sujet: Biological Sciences
• Sous-sujet: Molecular Biology

Provides an interdisciplinary introduction to peptide science, covering their properties and synthesis, as well as many contemporary applications

Peptides are biomolecules comprised of amino acids which play an important role in modulating many physiological processes in our body. This book presents an interdisciplinary approach and general introduction to peptide science, covering contemporary topics including their applicability in therapeutics, peptide hormones, amyloid structures, self-assembled structures, hydrogels, and peptide conjugates including lipopeptides and polymer-peptide conjugates. In addition, it discusses basic properties and synthesis clearly and concisely.

Taking a logical approach to the subject, Introduction to Peptide Science gives readers the fundamental knowledge that is required to understand the cutting-edge material which comes later in the book. It offers readers in-depth chapter coverage of the basic properties of peptides; synthesis; amyloid and peptide aggregate structures; antimicrobial peptides and cell-penetrating peptides; and peptide therapeutics and peptide hormones.

• Introduces readers to peptide science, including synthesis and properties
• Provides unique content covering properties, synthesis, self-assembly, aggregation, and applications
• Summarizes contemporary topics in an accessible fashion including applications in therapeutics, peptide hormones, amyloid structures, self-assembled structures, hydrogels, and peptide conjugates including lipopeptides
• Presented at an introductory level for the benefit of students and researchers who are new to the subject

Introduction to Peptide Science is an ideal text for undergraduate students of chemistry, biochemistry, and other related biological subjects, and will be a valuable resource for postgraduate students and researchers involved in peptide science and its applications.

1
Basic Properties

1.1 INTRODUCTION

Peptides and proteins are essential biological molecules and assemblies, and many structures and functions of organisms are derived by using them. Peptides and proteins comprise chains of amino acids and are produced from DNA in the ribosome via messenger RNA through three‐letter codons, i.e. each amino acid is represented by a triplet of nucleotides. Peptides are also known as ‘polypeptides’ to signify that they are polymers formed of amino acids. In fact, short peptides as considered in this book have the properties of oligomers rather than polymers.

Although there is no rigorous definition of the difference between peptides and proteins in this book, a typical peptide would have up to 100 residues, and longer chains would be considered proteins. In fact, standard synthesis methods lead to peptides up to 50–60 residues in length, which may also be considered a cut‐off, with somewhat larger chains being described as ‘mini‐proteins’.

This chapter is organized as follows. In Section 1.2, the essential properties of the 20 standard natural amino acids that peptides and proteins are built from are first considered, including an analysis of reactivity, charge, and hydrophobicity. When incorporated in a peptide or protein, the term ‘residue’ is used for the group formed from the corresponding amino acid. Non‐natural residues that are found in a few natural and synthetic peptides are also introduced in Section 1.2, especially those which are mentioned in peptide sequences elsewhere in this book. Then, in Section 1.3, the nature and geometry of the peptide bond are considered. The main secondary structures adopted by peptides are discussed in Section 1.4. There follows (Section 1.5) a description of characterization methods used to determine peptide structure and conformation. The chapter concludes with a list of useful peptide websites and selected software, including databases and property calculators.

1.2 PROPERTIES OF AMINO ACIDS

Amino acids are chiral molecules, meaning that there is a distinct spatial arrangement of substituents around the central backbone carbon atom, which is termed a C_α atom. This is a stereogenic centre. There are two possible arrangements with different ‘handedness’, which are mirror images. These forms are termed enantiomers. There are two forms, termed L‐ and D‐amino acids (note the use of a small capital letter). In the L form of a residue in a peptide, the substituents are arranged as shown in Figure 1.1, which can be remembered via the CORN mnemonic, with the CO, R, and N groups in a clockwise configuration from left, when viewed along the bond to the H atom. In nature, peptide and protein structures are almost entirely built from L‐amino acids. Molecules that contain amino acids may have more than one stereocentre; for example, Figure 1.2 shows the diastereomers of thre...