http://www.loc.gov/mods/v3 http://www.loc.gov/standards/mods/v3/mods-3-2.xsd
Identification and characterization of Babesia equi cysteine protease
Babesia equi is a tick-borne hemoprotozoan parasite causing equine babesiosis. Cysteine pretenses (CP) are endopeptidases widely distributed in nature and have been identified in a number of protozoan parasites. The B. equi parasite extracts showed major CP activities correspond to 90, 30- 34, and 18-23 kDa Mr proteolytic bands on the SDS-polyacrylamide gel copolymerised with gelatin substrate. Between 18-34 kDa, at least seven Cps were identified, with apparent 34, 32, 31, 30, 23, 19, and 18 kDa Mr. The B. equi parasite extract also was shown to be involved in equine hemoglobin degradation in vitro. A synthetic peptide based on a B. equi CP homology PCR fragment sequence Cys1a reported in the GenBank was used to raise an antiserum in rabbits. The rabbit antiserum recognized two putative CPs contained in the B. equi parasite extract with apparent 28 and 16 kDa Mr. The 28 kDa CP detected by the antiserum was likely the 23 kDa protein with CP activity on gelatin substrate gel. Equine sera with known antibody activities against B. equi did not react well with the 28 and 16 kDa antigens, suggesting that neither is immunodominant. Two B. equi CP gene sequences (Cys1b and Cys2) were obtained using 5'- and 3'- RACE by gene specific primers derived from the Cys1a sequence. The Cys1b and Cys2 have 97% and 62% AA homology with Cys1a, respectively. The Cys1b has the putative N-terminal for the mature enzyme site. The mature enzyme region of Cys1b sequence has 218 amino acids and the predicted molecular mass is 23.7 kDa. Both sequences are papain-like and have high homology with T. annulate and F. parva. Cys1b has the main features of CP, including the presence of cysteine-histidine-asparigine as the catalytic triad and 6 cysteine residues. The abundant B. equi CPs could be important in parasite development and/or pathogenicity. They are potential targets for specific anti-protozoa drugs. The information acquired will be useful for structural based drug design.
"Major Subject: Veterinary Microbiology".
Issued also on microfiche from University Microfilm Inc.
Includes bibliographical references (leaves 89-110).