Barros T F, Puccia R
Departamento de Microbiologia, Imunologia e Parasitologia da Universidade Federal de São Paulo, São Paulo, SP, Brazil.
Yeast. 2001 Jul;18(10):981-8. doi: 10.1002/yea.745.
A LON gene homologue from the human pathogen Paracoccidioides brasiliensis (PbLON) has been cloned, sequenced and characterized. It encodes a putative ATP-dependent proteinase Lon, which in Saccharomyces cerevisisae (PIM1) is a heat-inducible protein involved in the degradation of abnormal or short-lived proteins in the mitochondria. The PbLON ORF is within a 3369 bp fragment interrupted by two introns located in the 3'segment. The 5' and 3' regions flanking the ORF contain sequences which resemble known transcription elements. Several transcription binding factor motifs have also been found, including sites for heat shock/stress response and nitrogen control. The deduced protein consists of 1063 residues containing a mitochondrial import signal at the N-terminus and conserved ATP-binding (GPPGVGKT) and serine catalytic (KDGPSAG) sites. It shares high identity with Lon homologues from S. cerevisiae (73%), Homo sapiens (62%) and Escherichia coli (56%). In P. brasiliensis, an MDJ1 putative gene has also been partially sequenced adjacent to PbLON, possibly sharing divergently orientated promoter elements. This chromosomal organization is interesting, since Mdj1p is a heat shock chaperone essential for substrate degradation by PIM1 in yeast.
已对来自人类病原体巴西副球孢子菌（PbLON）的LON基因同源物进行了克隆、测序和特性分析。它编码一种假定的ATP依赖性蛋白酶Lon，在酿酒酵母（PIM1）中，该蛋白酶是一种热诱导蛋白，参与线粒体中异常或短命蛋白的降解。PbLON开放阅读框位于一个3369 bp的片段内，该片段被位于3'端的两个内含子打断。开放阅读框两侧的5'和3'区域包含与已知转录元件相似的序列。还发现了几个转录结合因子基序，包括热休克/应激反应和氮控制位点。推导的蛋白质由1063个残基组成，在N端含有一个线粒体导入信号以及保守的ATP结合位点（GPPGVGKT）和丝氨酸催化位点（KDGPSAG）。它与酿酒酵母（73%）、智人（62%）和大肠杆菌（56%）的Lon同源物具有高度同源性。在巴西副球孢子菌中，一个假定的MDJ1基因也已在与PbLON相邻的位置进行了部分测序，可能共享方向相反的启动子元件。这种染色体组织很有趣，因为Mdj1p是酵母中PIM1降解底物所必需的热休克伴侣蛋白。
