Protein structural motifs

type of secondary structure

common motif of regular secondary structure in proteins; stretch of polypeptide chain typically 3 to 10 amino acids long with backbone in an extended conformation

small structural protein motif found mostly in transcriptional genes

200px|thumb|The λ repressor of bacteriophage lambda employs two helix-turn-helix motifs (left; green) to bind [[DNA (right; blue and red). The λ repressor protein in this image is a dimer.]]

(in a chain-like biological molecule, such as a protein or nucleic acid) supersecondary structure, which also appears in a variety of other molecules

DNA-binding structural motif

transcription regulator protein

protein structural motif found in proteins that bind nucleotides

InterPro Repeat

secondary protein structure

secondary structure motif of proteins

type of secondary structure

InterPro Domain

ATP-binding protein sequence motifs

element of secondary structure in proteins where the polypeptide chain reverses its overall direction

Type of protein secondary structure

membrane-spanning protein domain

right|thumb|Illustration of the β-sandwich from Tenascin C (PDB entry: ). Beta-sandwich or β-sandwich domains consisting of 80 to 350 amino acids occur commonly in proteins. They are characterized by two opposing antiparallel beta sheets (β-sheets). The number of strands found in such domains may differ from one protein to another. β-sandwich domains are subdivided in a variety of different folds. The immunoglobulin-type fold found in antibodies (Ig-fold) consists of a sandwich arrangement of 7-9 antiparallel β-strands arranged in two β-sheets with a Greek-key topology. The Greek-key topology

set of three congruent geometrical helices with the same axis

protein family

secondary protein structure

localized disruption of the regular hydrogen bonding of a beta sheet

Granin (chromogranin and secretogranin) is a protein family of regulated secretory proteins ubiquitously found in the cores of amine and peptide hormone and neurotransmitter dense-core secretory vesicles.