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Unique molecular architecture of silk fibroin in the waxmoth, Galleria mellonella.
J Biol Chem 2002; 277(25):22639-47JB

Abstract

Proteins of silk fibers are characterized by reiterations of amino acid repeats. Physical properties of the fiber are determined by the amino acid composition, the complexity of repetitive units, and arrangement of these units into higher order arrays. Except for very short motifs of 6-10 residues, the length of repetitive units and the number of these units concatenated in higher order assemblies vary in all spider and lepidopteran silks analyzed so far. This paper describes an exceptional silk protein represented by the 500-kDa heavy chain fibroin (H-fibroin) of the waxmoth, Galleria mellonella. Its non-repetitive N-terminal (175 residues) and C-terminal (60 residues) parts, the overall gene organization, and the nucleotide sequence around the TATA box show that it is homologous to the H-fibroins of other Lepidoptera. However, over 95% of the protein consists of highly ordered repetitive structures that are unmatched in other species. The repetitive region includes 11 assemblies AB(1)AB(1)AB(1)AB(2)(AB(2))AB(2) of remarkably conserved polypeptide repeats A (63 amino acid residues), B(1) (43 residues), and B(2) (18 residues). The repeats contain a high proportion of Gly (31.6%), Ala (23.8%), Ser (18.1%), and of residues with long hydrophobic side chains (16% for Leu, Ile, and Val combined). The presence of the GLGGLG and SSAASAA(AA) motifs suggests formation of pleated beta-sheets and their stacking into crystallites. Conspicuous conservation of the apolar sequence VIVI followed by DD or ED is interpreted as indicating the importance of hydrophobicity and electrostatic charge in H-fibroin cross-linking. The environment of G. mellonella larvae within bee cultures requires continuous production of silk that must be both strong and elastic. The spectacular arrangement of the repetitive H-fibroin region apparently evolved to meet these requirements.

Authors+Show Affiliations

Institute of Entomology, Academy of Sciences, and the Faculty of Biological Sciences, University of South Bohemia, Branisovská 31, 370 05 Ceské Budejovice, Czech Republic.No affiliation info available

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

11886872

Citation

Zurovec, Michal, and Frantisek Sehnal. "Unique Molecular Architecture of Silk Fibroin in the Waxmoth, Galleria Mellonella." The Journal of Biological Chemistry, vol. 277, no. 25, 2002, pp. 22639-47.
Zurovec M, Sehnal F. Unique molecular architecture of silk fibroin in the waxmoth, Galleria mellonella. J Biol Chem. 2002;277(25):22639-47.
Zurovec, M., & Sehnal, F. (2002). Unique molecular architecture of silk fibroin in the waxmoth, Galleria mellonella. The Journal of Biological Chemistry, 277(25), pp. 22639-47.
Zurovec M, Sehnal F. Unique Molecular Architecture of Silk Fibroin in the Waxmoth, Galleria Mellonella. J Biol Chem. 2002 Jun 21;277(25):22639-47. PubMed PMID: 11886872.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Unique molecular architecture of silk fibroin in the waxmoth, Galleria mellonella. AU - Zurovec,Michal, AU - Sehnal,Frantisek, Y1 - 2002/03/08/ PY - 2002/3/12/pubmed PY - 2002/7/20/medline PY - 2002/3/12/entrez SP - 22639 EP - 47 JF - The Journal of biological chemistry JO - J. Biol. Chem. VL - 277 IS - 25 N2 - Proteins of silk fibers are characterized by reiterations of amino acid repeats. Physical properties of the fiber are determined by the amino acid composition, the complexity of repetitive units, and arrangement of these units into higher order arrays. Except for very short motifs of 6-10 residues, the length of repetitive units and the number of these units concatenated in higher order assemblies vary in all spider and lepidopteran silks analyzed so far. This paper describes an exceptional silk protein represented by the 500-kDa heavy chain fibroin (H-fibroin) of the waxmoth, Galleria mellonella. Its non-repetitive N-terminal (175 residues) and C-terminal (60 residues) parts, the overall gene organization, and the nucleotide sequence around the TATA box show that it is homologous to the H-fibroins of other Lepidoptera. However, over 95% of the protein consists of highly ordered repetitive structures that are unmatched in other species. The repetitive region includes 11 assemblies AB(1)AB(1)AB(1)AB(2)(AB(2))AB(2) of remarkably conserved polypeptide repeats A (63 amino acid residues), B(1) (43 residues), and B(2) (18 residues). The repeats contain a high proportion of Gly (31.6%), Ala (23.8%), Ser (18.1%), and of residues with long hydrophobic side chains (16% for Leu, Ile, and Val combined). The presence of the GLGGLG and SSAASAA(AA) motifs suggests formation of pleated beta-sheets and their stacking into crystallites. Conspicuous conservation of the apolar sequence VIVI followed by DD or ED is interpreted as indicating the importance of hydrophobicity and electrostatic charge in H-fibroin cross-linking. The environment of G. mellonella larvae within bee cultures requires continuous production of silk that must be both strong and elastic. The spectacular arrangement of the repetitive H-fibroin region apparently evolved to meet these requirements. SN - 0021-9258 UR - https://www.unboundmedicine.com/medline/citation/11886872/Unique_molecular_architecture_of_silk_fibroin_in_the_waxmoth_Galleria_mellonella_ L2 - http://www.jbc.org/cgi/pmidlookup?view=long&pmid=11886872 DB - PRIME DP - Unbound Medicine ER -