title: Folding behavior of four silks of giant honey bee reflects the evolutionary conservation of aculeate silk proteins.
abstract: Multiple gene duplication events in the precursor of the Aculeata (bees, ants, hornets) gave rise to four silk genes. Whilst these homologs encode proteins with similar amino acid composition and coiled coil structure, the retention of all four homologs implies they each are important. In this study we identified, produced and characterized the four silk proteins from Apis dorsata, the giant Asian honeybee. The proteins were readily purified, allowing us to investigate the folding behavior of solutions of individual proteins in comparison to mixtures of all four proteins at concentrations where they assemble into their native coiled coil structure. In contrast to solutions of any one protein type, solutions of a mixture of the four proteins formed coiled coils that were stable against dilution and detergent denaturation. The results are consistent with the formation of a heteromeric coiled coil protein complex. The mechanism of silk protein coiled coil formation and evolution is discussed in light of these results.
authors.affiliation: Bee Protection Laboratory, Department of Biology, Faculty of Science, Chiang Mai University, Chiang Mai 50200, Thailand.
authors.forename: Jakkrawut
authors.initials: J
authors.lastname: Maitip
authors.affiliation: CSIRO, (The Commonwealth Scientific and Industrial Research Organization), Food and Nutrition Flagship, Canberra, Australian Capital Territory, Australia.
authors.forename: Holly E
authors.initials: HE
authors.lastname: Trueman
authors.affiliation: John Curtin School of Medical Research, Australian National University, Australian Capital Territory, Australia.
authors.forename: Benjamin D
authors.initials: BD
authors.lastname: Kaehler
authors.affiliation: John Curtin School of Medical Research, Australian National University, Australian Capital Territory, Australia.
authors.forename: Gavin A
authors.initials: GA
authors.lastname: Huttley
authors.affiliation: Bee Protection Laboratory, Department of Biology, Faculty of Science, Chiang Mai University, Chiang Mai 50200, Thailand. Electronic address: panuwan@gmail.com.
authors.forename: Panuwan
authors.initials: P
authors.lastname: Chantawannakul
authors.affiliation: CSIRO, (The Commonwealth Scientific and Industrial Research Organization), Food and Nutrition Flagship, Canberra, Australian Capital Territory, Australia.
authors.forename: Tara D
authors.initials: TD
authors.lastname: Sutherland
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001516:Bees / Q000235:genetics* / Q000378:metabolism; D019143:Evolution, Molecular; D019476:Insect Proteins / Q000737:chemistry / Q000235:genetics*; D008969:Molecular Sequence Data; D017510:Protein Folding; D017433:Protein Structure, Secondary; D017385:Sequence Homology; D047011:Silk / Q000737:chemistry / Q000235:genetics*
chemical_list: D019476:Insect Proteins; D047011:Silk
keywords: Apis dorsata; Coiled coil; Honeybee; Recombinant silk