title: Characterization of S-adenosylmethionine synthetase in Cryptosporidium parvum (Apicomplexa).
abstract: The S-adenosylmethionine synthetase gene of the apicomplexan Cryptosporidium parvum (CpSAMS), an agent of diarrhea in immunocompromised and healthy humans and animals is described. CpSAMS is a single-copy, intronless gene of 1221 bp encoding a polypeptide of 406 amino acids with a molecular mass of 44.8 kDa. The gene is AT-rich (61.8%). CpSAMS was expressed in Escherichia coli TB1 cells as a fusion with maltose binding protein. The activity of the recombinant fusion was assayed, and was found to be inhibited by the methionine analog cycloleucine. In order to determine whether CpSAMS was differentially expressed during the life cycle of C. parvum, HCT-8 cells were infected with C. parvum and assayed over 72 h. Semi-quantitative reverse transcription-polymerase chain reaction (RT-PCR) confirmed the differential expression of CpSAMS.
authors.affiliation: Wadsworth Center, New York State Department of Health, P.O. Box 22002, Albany, NY 12201-2002, USA.
authors.forename: Jan
authors.initials: J
authors.lastname: Slapeta
authors.forename: Frantisek
authors.initials: F
authors.lastname: Stejskal
authors.forename: Janet S
authors.initials: JS
authors.lastname: Keithly
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D015139:Blotting, Southern; D002352:Carrier Proteins / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D002460:Cell Line; D016785:Cryptosporidium parvum / Q000201:enzymology* / Q000235:genetics; D003515:Cycloleucine / Q000494:pharmacology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism; D015870:Gene Expression; D020869:Gene Expression Profiling; D007700:Kinetics; D058619:Maltose-Binding Proteins; D008716:Methionine Adenosyltransferase / Q000737:chemistry / Q000235:genetics* / Q000302:isolation & purification / Q000378:metabolism; D008969:Molecular Sequence Data; D008970:Molecular Weight; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D017422:Sequence Analysis, DNA; D017385:Sequence Homology; D014170:Transformation, Genetic
chemical_list: D002352:Carrier Proteins; D004791:Enzyme Inhibitors; D058619:Maltose-Binding Proteins; D011993:Recombinant Fusion Proteins; D003515:Cycloleucine; D008716:Methionine Adenosyltransferase