Nucleotide Sequences of the -proA and ProB Genes of Treponema pallidum, the Syphilis Agent

Abstract

The nucleotide sequences of the putative proA and proB genes of Treponema pallidum were determined. The pro A gene is 1287 nucleotides long and encodes a 428 amino acid protein with a predicted M_r of 46.6 kDa. The proB gene is 891 nucleotides long and encodes a 296 amino acid protein with a predicted M_r of 31.3 kDa. The deduced amino acid sequences of the treponemal ProA and ProB proteins have a high degree of homology to the amino acid sequences of several bacterial ProA and ProB proteins. The order of the T. pallidum pro genes (proA/proB) is unique in comparison to the order of these genes in other bacteria. The identification of the putative proA and proB genes in T. pallidum, coupled with the previous identification of the proC gene, strongly suggests that this fastidious spirochete is capable of proline biosynthesis.

Cystatin A is a cysteine proteinase inhibitor with a molecular mass of 11 kDa, and is located mainly in the keratohyaline granules of the stratum granulosum and the cornified envelope of the stratum corneum in the epidermis. In this study, we demonstrated the genomic structure of this proteinase inhibitor in which there were three exorts of 111 bp, 102 bp and 226 bp in length, while the lengths of the 1st and 2nd intron were approximately 14 Kbp and 4 Kbp, respectively. The conserved sequence of QWAG was encoded in the 2nd exon and was not inserted by any introns. There were binding sites for SP-1 and AP-2 in the promoter region and an AP-1 binding site in the 1st intron. The successful amplification of each exon of cystatin A may possibly contribute to the detection of the genomic abnormality of some skin disorders e.g. keratinization disorder, chronic bacterial infection or photophobia.

Key Words:

• Proline biosynthesis
• spirochete
• syphilis
• Treponema pallidum
• Cystatin A
• cysteine proteinase inhibitor
• genomic structure
• exon
• intron
• promoter