Molecule Tutorials - Herong's Tutorial Examples - v1.26, by Herong Yang
What Is Protein
This section provides a quick introduction of protein, which is a peptide found in living organisms in nature. A protein is usually a long chain of amino acid residues from the 20 common amino acids, coiled and folded into a 3-dimensional conformation.
What Is Protein? - A protein is a peptide found in living organisms in nature. A protein is usually a long chain of amino acid residues from the 20 common amino acids, coiled and folded into a 3-dimensional conformation.
What Is Protein Sequence? - A protein sequence is a sequence of abbreviations of amino acids whose residues are linked by peptide bonds to form the protein. The sequence starts from the amino-terminal (N-terminal) of the chain and stops at the carboxyl-terminal (C-Terminal) of the chain.
If we connect the peptide bonds and their neighbor bonds to central C atoms of neighbor amino acid residues, it forms the backbone of the protein sequence. This backbone is also called protein backbone.
For example, the smallest protein found in nature is called Trp-Cage, which has only 20 amino acid residues linked in the following sequence:
NLYIQWLKDGGPSSGRPPPS
The following picture shows the molecule structure of the Trp-Cage protein (source: biomolecular-modeling.com). The protein backbone is shown as a darker line in the picture.
The following picture shows the folded 3-dimensional conformation of Trp-Cage protein found in nature (source: biomolecular-modeling.com):
The largest protein is call Titin, which has 27,000 amino acid residues.
Table of Contents
Molecule Names and Identifications
Peptide, Peptide Bond, Amino Acid Residues
Protein Visualization - Ribbon Diagram
Composed Proteins or Protein Complexes
wwpdb.org - Worldwide PDB (Protein Data Bank)
Nucleobase, Nucleoside, Nucleotide, DNA and RNA
ChEMBL Database - European Molecular Biology Laboratory
PubChem Database - National Library of Medicine
INSDC (International Nucleotide Sequence Database Collaboration)
HGNC (HUGO Gene Nomenclature Committee)