title: Coiled-coil length: Size does matter.
abstract: Protein evolution is governed by processes that alter primary sequence but also the length of proteins. Protein length may change in different ways, but insertions, deletions and duplications are the most common. An optimal protein size is a trade-off between sequence extension, which may change protein stability or lead to acquisition of a new function, and shrinkage that decreases metabolic cost of protein synthesis. Despite the general tendency for length conservation across orthologous proteins, the propensity to accept insertions and deletions is heterogeneous along the sequence. For example, protein regions rich in repetitive peptide motifs are well known to extensively vary their length across species. Here, we analyze length conservation of coiled-coils, domains formed by an ubiquitous, repetitive peptide motif present in all domains of life, that frequently plays a structural role in the cell. We observed that, despite the repetitive nature, the length of coiled-coil domains is generally highly conserved throughout the tree of life, even when the remaining parts of the protein change, including globular domains. Length conservation is independent of primary amino acid sequence variation, and represents a conservation of domain physical size. This suggests that the conservation of domain size is due to functional constraints.
authors.affiliation: Instituto Gulbenkian de Ciência, Oeiras, 2780-156, Portugal.
authors.forename: Jaroslaw
authors.identifier: http://orcid.org/0000-0001-9271-5529
authors.initials: J
authors.lastname: Surkont
authors.affiliation: Instituto Gulbenkian de Ciência, Oeiras, 2780-156, Portugal.|Physiology Course, Marine Biological Laboratory, Woods Hole, Massachusetts, 02543.
authors.forename: Yoan
authors.initials: Y
authors.lastname: Diekmann
authors.affiliation: Physiology Course, Marine Biological Laboratory, Woods Hole, Massachusetts, 02543.|Emory University School of Medicine, Atlanta, Georgia, 30322.
authors.forename: Pearl V
authors.initials: PV
authors.lastname: Ryder
authors.affiliation: Instituto Gulbenkian de Ciência, Oeiras, 2780-156, Portugal.|Physiology Course, Marine Biological Laboratory, Woods Hole, Massachusetts, 02543.
authors.forename: Jose B
authors.initials: JB
authors.lastname: Pereira-Leal
mesh_terms: D020816:Amino Acid Motifs; D008958:Models, Molecular; D010455:Peptides / Q000737:chemistry; D000072417:Protein Domains; D055550:Protein Stability; D011506:Proteins / Q000737:chemistry*
chemical_list: D010455:Peptides; D011506:Proteins
keywords: indel; protein domain; protein evolution; protein size; sequence repeats