title: Activity and sequence characterization of two cysteine proteases in the digestive tract of the reduviid bug Triatoma infestans.
abstract: Cathepsin B- and cathepsin L-like activities were identified in gut extracts of the blood-sucking bug Triatoma infestans using specific substrates and inhibitors. Activities decreased during the first 2 days after feeding but increased to a maximum value at 5 and 10 days post feeding. The deduced 332 and 328 amino acid sequences showed high levels of identity (50-60%) to other insect cathepsin B- and L-like proteases, respectively. The three amino acid residues of the catalytic domain, CHN, and the GCNGG motif were conserved in both cathepsins, but the occluding loop, characterizing B-like cathepsins, was present only in one. ERFNIN and GNFD motifs occurred in the other sequence, defining it as cathepsin L-like. The cathepsin B-like gene was expressed at low, constitutive levels in unfed and fed T. infestans.
authors.affiliation: Department of Special Zoology, Ruhr-University, Bochum, Germany. astrid.kollien@ruhr-uni-bochum.de
authors.forename: A H
authors.initials: AH
authors.lastname: Kollien
authors.forename: P J
authors.initials: PJ
authors.lastname: Waniek
authors.forename: A J
authors.initials: AJ
authors.lastname: Nisbet
authors.forename: P F
authors.initials: PF
authors.lastname: Billingsley
authors.forename: G A
authors.initials: GA
authors.lastname: Schaub
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002401:Cathepsin B / Q000235:genetics / Q000378:metabolism*; D056668:Cathepsin L; D002403:Cathepsins / Q000235:genetics / Q000378:metabolism*; D003546:Cysteine Endopeptidases / Q000235:genetics / Q000378:metabolism*; D017931:DNA Primers; D004435:Eating / Q000502:physiology; D041981:Gastrointestinal Tract / Q000378:metabolism*; D020869:Gene Expression Profiling; D008969:Molecular Sequence Data; D021141:Nucleic Acid Amplification Techniques; D020133:Reverse Transcriptase Polymerase Chain Reaction; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA; D014224:Triatoma / Q000201:enzymology* / Q000502:physiology
chemical_list: D017931:DNA Primers; D002403:Cathepsins; D003546:Cysteine Endopeptidases; D002401:Cathepsin B; D056668:Cathepsin L