TY - JOUR
T1 - Molecular cloning and characterization of the genes encoding two isoforms of cysteine synthase in the enteric protozoan parasite Entamoeba histolytica1
AU - Nozaki, Tomoyoshi
AU - Asai, Takashi
AU - Kobayashi, Seiki
AU - Ikegami, Fumio
AU - Noji, Masaaki
AU - Saito, Kazuki
AU - Takeuchi, Tsutomu
N1 - Funding Information:
The authors express their appreciation to Jun-ichi Sanuki, Miki Nakazawa, and Yasuo Shigeta at Keio University, School of Medicine for technical assistance. This work was supported by the National Grant-in-Aid for the Establishment of High-Tech-Research Center in a Private University from the Ministry of Education of Japan, ‘Research for the Future’ Program (#JSPS-RFTF97L00701) from the Japan Society for the Promotion of Science, and a Grant for Promotion of AIDS Research from The Ministry of Health and Welfare of Japan.
PY - 1998/11/30
Y1 - 1998/11/30
N2 - The enteric protozoan parasite Entamoeba histolytica was shown to possess cysteine synthase (CS) activity. The cDNA and genomic clones that encode two isoforms of the E. histolytica CS were isolated and characterized from a clonal strain of E. histolytica by genetic complementation of the cysteine-auxotrophic Escherichia coli NK3 with an E. histolytica cDNA library. The two types of the E. histolytica CS genes differed from each other by three nucleotides, two of which resulted in amino acid substitution. Deduced amino acid sequences of the E. histolytica CS, with a calculated molecular mass of 36 721 Da and an isoelectric point of 6.39, exhibited 38-48% identity with CS of bacterial and plant origins. The absence of the amino-terminal transit peptide in the deduced protein sequences and the presence of the CS protein mainly in the supernatant fraction of the amoebic lysate after cellular fractionation suggested that the identified E. histolytica CS genes encoded cytosolic isoforms. Substrate specificity of the recombinant E. histolytica CS was similar to that of plant CS. Phylogenetic analysis indicates that the amoebic CS, first described in Protozoa, does not belong to any families of the CS superfamily, and represents a new family. Copyright (C) 1998 Elsevier Science B.V.
AB - The enteric protozoan parasite Entamoeba histolytica was shown to possess cysteine synthase (CS) activity. The cDNA and genomic clones that encode two isoforms of the E. histolytica CS were isolated and characterized from a clonal strain of E. histolytica by genetic complementation of the cysteine-auxotrophic Escherichia coli NK3 with an E. histolytica cDNA library. The two types of the E. histolytica CS genes differed from each other by three nucleotides, two of which resulted in amino acid substitution. Deduced amino acid sequences of the E. histolytica CS, with a calculated molecular mass of 36 721 Da and an isoelectric point of 6.39, exhibited 38-48% identity with CS of bacterial and plant origins. The absence of the amino-terminal transit peptide in the deduced protein sequences and the presence of the CS protein mainly in the supernatant fraction of the amoebic lysate after cellular fractionation suggested that the identified E. histolytica CS genes encoded cytosolic isoforms. Substrate specificity of the recombinant E. histolytica CS was similar to that of plant CS. Phylogenetic analysis indicates that the amoebic CS, first described in Protozoa, does not belong to any families of the CS superfamily, and represents a new family. Copyright (C) 1998 Elsevier Science B.V.
KW - Anti-oxidant
KW - Cysteine
KW - Cysteine synthase
KW - Entamoeba histolytica
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U2 - 10.1016/S0166-6851(98)00129-7
DO - 10.1016/S0166-6851(98)00129-7
M3 - Article
C2 - 9879885
AN - SCOPUS:0032583190
VL - 97
SP - 33
EP - 44
JO - Molecular and Biochemical Parasitology
JF - Molecular and Biochemical Parasitology
SN - 0166-6851
IS - 1-2
ER -