Determination of the site of disulfide linkage between heavy and light chains of silk fibroin produced by Bombyx mori.
The analysis of fibroin secretion-deficient 'naked-pupa' mutant silkworms has suggested that the disulfide linkage between heavy (H) and light (L) chains of fibroin, produced by the silkworm, Bombyx mori, is essential in its efficient large-scale secretion from the posterior silk gland cells. However, the site of disulfide-linkage between H- and L-chains has not been determined. In this study, cysteine residues involved in the single disulfide linkage between H- and L-chains were identified as the twentieth residue from the carboxyl terminus of H-chain (Cys-c20) and Cys-172 of L-chain by sequencing of genomic clones and peptide analysis. Furthermore, Cys-c4 (fourth residue from the carboxyl terminus) and Cys-c1 at the carboxyl terminus of H-chain were shown to form an intramolecular disulfide bond.
Tanaka
K
K
Laboratory of Molecular Biology, Department of Molecular and Cell Biology, Graduate School of Agricultural Science, Tohoku University, 1-1 Tsutsumidori-Amamiyamachi, Aoba-ku, Sendai 981-8555, Japan.
Kajiyama
N
N
Ishikura
K
K
Waga
S
S
Kikuchi
A
A
Ohtomo
K
K
Takagi
T
T
Mizuno
S
S
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D001665:Binding Sites; D012831:Bombyx / Q000235:genetics / Q000378:metabolism*; D003545:Cysteine / Q000737:chemistry*; D004220:Disulfides / Q000737:chemistry*; D005349:Fibroins / Q000737:chemistry*; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000737:chemistry; D014357:Trypsin
D004220:Disulfides; D010446:Peptide Fragments; D005349:Fibroins; D014357:Trypsin; D003545:Cysteine