title: Long loops in proteins.
abstract: In proteins, loop regions which connect secondary structures are generally short (80% are <10 amino acids long). However, long loops, defined here as > or = 10 residues, do occur. Two types of long loop may be distinguished: those which connect adjacent regions of secondary structure ('long-closed') and those which connect distant secondary structures ('long-open'). Only 5% of all loops in proteins fall into the long-open class. Inspection of these unusual long-open loops reveals a higher percentage of proline residues and more helix-helix linkages than expected. Exposure to solvent is similar for long-open and long-closed loops. The role of these loops in protein folding is discussed.
authors.affiliation: Department of Biochemistry and Molecular Biology, University College London, UK.
authors.forename: A C
authors.initials: AC
authors.lastname: Martin
authors.forename: K
authors.initials: K
authors.lastname: Toda
authors.forename: H J
authors.initials: HJ
authors.lastname: Stirk
authors.forename: J M
authors.initials: JM
authors.lastname: Thornton
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002374:Catalase / Q000737:chemistry; D002417:Cattle; D003198:Computer Simulation; D016208:Databases, Factual; D008958:Models, Molecular; D008969:Molecular Sequence Data; D017510:Protein Folding; D017433:Protein Structure, Secondary; D012984:Software
chemical_list: D002374:Catalase