Structural and functional properties of chicken lysozyme fused serine-rich heptapeptides at the C-terminus.
Two serine-rich heptapeptides, Ser-Ser-Ser-Lys-Ser-Ser-Ser (S6K) and Ser-Ser-Ser-Ser-Ser-Ser-Ser (S7), were fused to the C-terminus of chicken lysozyme (Lz) by genetic modification to improve the functional properties of lysozyme. The cDNAs of S6K-lysozyme (S6K-Lz) and S7-lysozyme (S7-Lz) were inserted into the expression vector of Pichia pastoris and secreted in yeast cultivation medium. The secretion amounts of S6K-Lz and S7-Lz were about 60% of that of wild-type lysozyme (Wt-Lz). The CD spectra showed that the conformation of S6K-Lz and S7-Lz was conserved regardless of the attachment of serine-rich peptides. The denaturation curves of S6K-Lz and S7-Lz also showed that the conformational changes were very small. The lytic activity of S6K-Lz and S7-Lz was almost the same as that of Wt-Lz, while the bactericidal activity against Escherichia coli of S6K-Lz and S7-Lz was greatly increased. The acetic acid-urea PAGE of phosphatase-treated S6K-Lz and S7-Lz indicated the possibility of phosphorylation of the fused serine-rich heptapeptides.
Xu
Xiaohua
X
Department of Biological Chemistry, Yamaguchi University, Yamaguchi, Japan.
Kashima
Orie
O
Saito
Akira
A
Azakami
Hiroyuki
H
Kato
Akio
A
D000595:Amino Acid Sequence; D000818:Animals; D000900:Anti-Bacterial Agents / Q000737:chemistry / Q000494:pharmacology; D002645:Chickens; D004926:Escherichia coli / Q000187:drug effects; D009113:Muramidase / Q000737:chemistry* / Q000494:pharmacology*; D010766:Phosphorylation; D011487:Protein Conformation; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000494:pharmacology; D012694:Serine; D013329:Structure-Activity Relationship
D000900:Anti-Bacterial Agents; D011993:Recombinant Fusion Proteins; D012694:Serine; D009113:Muramidase