Previous Article | Next Article ![]()
Infect. Immun., 12 1996, 5000-5007, Vol 64, No. 12
H Tsai, PA Raj and LA Bobek
Human salivary histatins possess fungicidal and bactericidal activities.
The current investigation evaluates the structure-function relationship of
histatins with regard to their candidacidal activity by using recombinant
histatin-5 and its variants produced in Escherichia coli. The purified
recombinant histatins were examined for their candidacidal activity and
secondary structure. The m21 (with Lys-13 replaced by Thr
[Lys-13-->Thr]) and m71 (Lys-13-->Glu) variants are significantly
less effective than recombinant histatin-5 in killing Candida albicans,
suggesting that Lys-13 is critical for candidacidal activity. The m68
(Lys-13-->Glu and Arg-22-->Gly) variant is significantly less potent
than the recombinant histatin-5 as well as m71, indicating that Arg-22 is
crucial for the cidal activity. The candidacidal activities of m1
(Arg-12-->Ile), m2 (Arg-12-->Ile and Lys- 17-->Asp), m12
(Arg-12-->Lys and His-21-->Leu), and m70 (His-19-->Pro and
His-21-->Arg) variants, however, are comparable to that of recombinant
histatin-5, indicating that Arg-12, Lys-17, His-19, and His- 21 are not
functionally important. The conformational preferences of histatin-5 and
variants were determined by circular dichroism. The results indicate that
all proteins have a strong tendency to adopt alpha-helical conformation in
trifluoroethanol. Previously, we have shown that the alpha-helical
conformation is one of the important structural requirements for eliciting
appreciable candidacidal activity. Collectively, the data suggest that in
addition to the helical conformation, specific residues such as Lys-13 and
Arg-22 in the sequence of histatin-5 are, indeed, important for
candidacidal activity.
Copyright © 1996, American Society for Microbiology
Candidacidal activity of recombinant human salivary histatin-5 and variants
Department of Oral Biology, School of Dental Medicine, State University of New York at Buffalo, 14214, USA.
This article has been cited by other articles:
| J. Bacteriol. | J. Virol. | Eukaryot. Cell |
|---|
| Microbiol. Mol. Biol. Rev. | Clin. Vaccine Immunol. | All ASM Journals |
|---|