de Viragh P A, Sanglard D, Togni G, Falchetto R, Monod M
Laboratoire de Mycologie, Centre Hospitalier Universitaire Vaudois, Lausanne, Switzerland.
J Gen Microbiol. 1993 Feb;139(2):335-42. doi: 10.1099/00221287-139-2-335.
Candida parapsilosis secretes an inducible acid protease (ACP) when cultivated in the presence of bovine serum albumin as the sole nitrogen source. In order to clone the ACP gene (ACP) of C. parapsilosis, a genomic library was screened with C. tropicalis ACP as the probe. Two different ORFs, ACPR and ACPL, were found to hybridize with the C. tropicalis ACP. ACPR contained a DNA sequence in agreement with the N-terminal amino acid sequence of C. parapsilosis ACP isolated from culture supernatants. ACPR was shown to be expressed and functional in a C. tropicalis acid protease mutant (acp) and with SDS-PAGE the protein product showed the same mobility as the ACP secreted by C. parapsilosis. These results imply that ACPR encodes the C. parapsilosis ACP. The deduced amino acid sequence of ACPR is similar to the amino acid sequence of proteases of the pepsin family. As in the case of the C. tropicalis and C. albicans ACP, the 5' extremity of ACPR revealed a propeptide containing two Lys-Arg amino acid pairs that have been identified as peptidase processing sites in several yeast-secreted peptides and protein precursors. As judged from the deduced amino acid sequences, the ACPL product would be similar to that of ACPR; however, a protein corresponding to ACPL was not found in supernatants from C. parapsilosis liquid cultures. In addition, ACPL did not complement the C. tropicalis acp mutant. We conclude that ACPL is a pseudogene or serves an as yet unidentified function.
近平滑念珠菌在以牛血清白蛋白作为唯一氮源培养时会分泌一种诱导性酸性蛋白酶（ACP）。为了克隆近平滑念珠菌的ACP基因（ACP），以热带念珠菌ACP为探针筛选基因组文库。发现两个不同的开放阅读框（ORF），即ACPR和ACPL，与热带念珠菌ACP杂交。ACPR包含的DNA序列与从培养上清液中分离出的近平滑念珠菌ACP的N端氨基酸序列一致。已证明ACPR在热带念珠菌酸性蛋白酶突变体（acp）中表达且具有功能，通过SDS-PAGE分析，该蛋白产物与近平滑念珠菌分泌的ACP具有相同的迁移率。这些结果表明ACPR编码近平滑念珠菌的ACP。ACPR推导的氨基酸序列与胃蛋白酶家族蛋白酶的氨基酸序列相似。与热带念珠菌和白色念珠菌ACP的情况一样，ACPR的5'末端显示有一个前肽，其中包含两个Lys-Arg氨基酸对，在几种酵母分泌的肽和蛋白质前体中已被确定为肽酶加工位点。从推导的氨基酸序列判断，ACPL产物与ACPR相似；然而，在近平滑念珠菌液体培养物的上清液中未发现与ACPL相对应的蛋白质。此外，ACPL不能互补热带念珠菌acp突变体。我们得出结论，ACPL是一个假基因或具有尚未明确的功能。
