Editing Coiled coil (section)

{{Short description|Structural motif in proteins}}
{{other uses|Coiled coil (disambiguation)}}
[[Image:GCN4 coiled coil dimer 1zik rainbow.png|thumb|200px|right|Figure 1: The classic example of a coiled coil is the GCN4 [[leucine zipper]] (PDB accession code 1zik), which is a parallel, left-handed [[homodimer]]. However, many other types of coiled coil exist.]]

A '''coiled coil''' is a [[structural motif]] in [[Protein|proteins]] in which two to seven<ref name="Liu20062">{{cite journal |vauthors=Liu J, Zheng Q, Deng Y, Cheng CS, Kallenbach NR, Lu M |date=Oct 2006 |title=A seven-helix coiled coil |journal=Proceedings of the National Academy of Sciences of the United States of America |volume=103 |issue=42 |pages=15457–62 |bibcode=2006PNAS..10315457L |doi=10.1073/pnas.0604871103 |pmc=1622844 |pmid=17030805 |doi-access=free}}</ref> [[Alpha helix|alpha-helices]] are coiled together like the strands of a rope. ([[Protein dimer|Dimers]] and [[Protein trimer|trimers]] are the most common types.) They have been found in roughly 5-10% of proteins and have a variety of functions.<ref>{{Cite journal |last1=Szczepaniak |first1=Krzysztof |last2=Bukala |first2=Adriana |last3=da Silva Neto |first3=Antonio Marinho |last4=Ludwiczak |first4=Jan |last5=Dunin-Horkawicz |first5=Stanislaw |date=2021-04-01 |editor-last=Elofsson |editor-first=Arne |title=A library of coiled-coil domains: from regular bundles to peculiar twists |url=https://academic.oup.com/bioinformatics/article/36/22-23/5368/6039120 |journal=Bioinformatics |language=en |volume=36 |issue=22–23 |pages=5368–5376 |doi=10.1093/bioinformatics/btaa1041 |issn=1367-4803 |pmc=8016460 |pmid=33325494}}</ref> They are one of the most widespread motifs found in protein-protein interactions. To aid protein study, several tools have been developed to predict coiled-coils in protein structures.<ref>{{Cite journal |last1=Walshaw |first1=John |last2=Woolfson |first2=Derek N |date=2001-04-13 |title=SOCKET: a program for identifying and analysing coiled-coil motifs within protein structures11Edited by J. Thornton |url=https://www.sciencedirect.com/science/article/pii/S0022283601945450 |journal=Journal of Molecular Biology |volume=307 |issue=5 |pages=1427–1450 |doi=10.1006/jmbi.2001.4545 |pmid=11292353 |issn=0022-2836|url-access=subscription }}</ref> Many coiled coil-type proteins are involved in important biological functions, such as the regulation of [[gene expression]] — e.g., [[Transcription factor|transcription factors]]. Notable examples are the [[Oncoprotein|oncoproteins]] [[c-Fos]] and [[c-Jun]], as well as the muscle protein [[tropomyosin]].