Identification and enzymatic activities of four protein disulfide isomerase (PDI) isoforms of Leishmania amazonensis

• Published in: Parasitology research (1987) Vol. 102; no. 3; pp. 437 - 446
• Main Authors: Hong, B. X, Soong, L
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Berlin/Heidelberg : Springer-Verlag 01.02.2008; Springer-Verlag; Springer
• Subjects: Amino Acid Sequence; Animals; Biological and medical sciences; Biomedical and Life Sciences; Biomedicine; Conserved Sequence; DNA Primers; Fundamental and applied biological sciences. Psychology; Gene Amplification; General aspects; General aspects and techniques. Study of several systematic groups. Models; Immunology; Invertebrates; Isoenzymes - isolation & purification; Isoenzymes - metabolism; Leishmania; Leishmania - enzymology; Leishmaniasis; Medical Microbiology; Mice; Microbiology; Molecular Sequence Data; Original Paper; Polymerase Chain Reaction; Protein disulfide isomerase (PDI); Protein Disulfide-Isomerases - genetics; Protein Disulfide-Isomerases - isolation & purification; Protein Disulfide-Isomerases - metabolism; Protozoan Proteins - genetics; Protozoan Proteins - isolation & purification; Protozoan Proteins - metabolism; RNA, Protozoan - genetics; RNA, Protozoan - isolation & purification; Sequence Alignment; Sequence Homology, Amino Acid; Protein disulfide isomerase (PDI); Kinetoplastida; Protozoa; Isomerases; Enzymatic activity; Enzyme; Leishmania; Parasite; Leishmania amazonensis; Protein
• ISSN: 0932-0113; 1432-1955
• DOI: 10.1007/s00436-007-0784-4

Leishmania parasites primarily infect cells of macrophage lineage and can cause leishmaniasis in the skin, mucosal, and visceral organs, depending on both host- and parasite-derived factors. The protein disulfide isomerases (PDIs) are thiol-disulfide oxidoreductases that catalyze the formation, reduction, and isomerization of disulfide bonds of proteins in cells. Although four Leishmania PDI genes are functionally inferred from homology in the genome sequences, only two of them have been expressed as active proteins to date. The functional relationship among various PDI enzymes remains largely unclear. In this study, we expressed and partially characterized all four L. amazonensis PDIs encoding 52-, 47-, 40-, and 15-kDa proteins. Homology analysis showed that the sequence identity between L. amazonensis (New World) PDIs and their counterpart PDI sequences from L. major (Old World) ranged from 76% to 99%. Kinetic characterization indicated that while the 15-, 40-, and 47- kDa PDI proteins displayed both insulin isomerase and reductase activities, the 52-kDa protein had only isomerase activity with no detectable reductase activity. All four PDI proteins were recognized by sera from L. amazonensis-infected mice and were sensitive to inhibition by standard PDI inhibitors. This study describes the enzymatic activities of recombinant L. amazonensis PDIs and suggests a role for these proteins in parasite development.