A novel chitin-binding protein identified from the peritrophic membrane of the cabbage looper, Trichoplusia ni

• Published in: Insect biochemistry and molecular biology Vol. 35; no. 11; pp. 1224 - 1234
• Main Authors: Guo, Wei, Li, Guoxun, Pang, Yi, Wang, Ping
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01.11.2005
• Subjects: Amino Acid Sequence; amino acid sequences; Animals; Arthropoda; Base Sequence; binding properties; binding proteins; Blotting, Western; Brassica; chitin; Chitin - metabolism; chitin deacetylase-like domain; Chitin deacetylase-like protein; Chitin-binding protein; DNA, Complementary; Electrophoresis, Polyacrylamide Gel; expressed sequence tags; Helicoverpa zea; Heliothis virescens; Insect Proteins - chemistry; Insect Proteins - metabolism; Membrane Proteins - chemistry; Membrane Proteins - metabolism; Midgut; Molecular Sequence Data; Moths - chemistry; nucleotide sequences; Peritrophic membrane; Protein Binding; sequence homology; Sequence Homology, Amino Acid; TnPM-P42; Trichoplusia ni; Peritrophic membrane; Chitin deacetylase-like protein; Trichoplusia ni; Midgut; Chitin-binding protein; TnPM-P42
• ISSN: 0965-1748; 1879-0240
• DOI: 10.1016/j.ibmb.2005.06.003

A novel midgut peritrophic membrane (PM) protein, TnPM-P42, was identified from the cabbage looper, Trichoplusia ni. TnPM-P42 was shown as a 42 kDa protein by SDS-PAGE analysis and appeared to be associated with the PM throughout its entire length. In T. ni larvae, the midgut is the only tissue where TnPM-P42 could be detected during the feeding period of the larvae. TnPM-P42 has chitin-binding activity and is strongly associated with the PM, which is similar to the currently known peritrophin type PM proteins. However, TnPM-P42 represents a unique family of proteins distinctly different from the peritrophin type PM proteins in its sequence characteristics. TnPM-P42 does not contain the peritrophin domain which is present in all the currently known PM proteins, but instead has a chitin deacetylase-like domain. Sequence similarity search of the GenBank database did not result in identification of any known proteins with a significant overall sequence similarity to the TnPM-P42. However, expressed sequence tags (ESTs) from various arthropods were identified to code for proteins with high sequence similarities to TnPM-P42, indicating the presence of TnPM-P42 homologs in other arthropods. Consistent with the identification of various ESTs from arthropods, Western blot analysis demonstrated the presence of a TnPM-P42-like protein in the PMs from Heliothis virescens and Helicoverpa zea larvae. The sequence characteristics of TnPM-P42 indicate that TnPM-P42 represents a novel family of insect proteins. However, its biochemical and physiological functions require further investigation.