Pereira M, Felipe M S, Brígido M M, Soares C M, Azevedo M O
Departamento de Ciências Fisiológicas, Instituto de Ciências Biológicas, Universidade Federal de Goiás, Goiânia, GO, Brasil, 74001-970.
Yeast. 2000 Mar 30;16(5):451-62. doi: 10.1002/(SICI)1097-0061(20000330)16:5<451::AID-YEA540>3.0.CO;2-O.
1,3-beta-D-glucan is a fungal cell wall polymer synthesized by the multi-subunit enzyme 1,3-beta-D-glucan synthase. A subunit of this integral membrane protein was first described as the product of the FKS1 gene from Saccharomyces cerevisiae using echinocandin mutants. Other FKS1 genes were also reported for Candida albicans, Aspergillus nidulans and Cryptococcus neoformans. Here, we report the nucleotide sequence of the first homologous FKS gene cloned from the pathogenic fungus Paracoccidioides brasiliensis. An open reading frame of 5942 bp was identified in the complete sequence, interrupted by two putative introns, the first close to the 5' end and the second close to the 3' end of the gene. A promoter region is also described containing consensus sequences such as canonical TATA and CAAT boxes and, possibly, multiple sites for glucose regulation by creA protein. The deduced sequence of 1926 amino acid show more than 85% similarity to FksAp from A. nidulans, and 71% to Fks1p and Fks2p from S. cerevisiae. Computational analysis of P. brasiliensis Fks1p suggests a similar structure to transmembrane proteins, such as FksAp, with the presence of two domains composed by hydrophobic helices that limit the putative highly hydrophilic catalytic domain within the cytoplasm.
1,3-β-D-葡聚糖是一种由多亚基酶1,3-β-D-葡聚糖合酶合成的真菌细胞壁聚合物。利用棘白菌素突变体，该整合膜蛋白的一个亚基首次被描述为酿酒酵母FKS1基因的产物。白色念珠菌、构巢曲霉和新型隐球菌也有其他FKS1基因的报道。在此，我们报道了从致病真菌巴西副球孢子菌中克隆的首个同源FKS基因的核苷酸序列。在完整序列中鉴定出一个5942 bp的开放阅读框，被两个推定的内含子打断，第一个靠近基因的5'端，第二个靠近3'端。还描述了一个启动子区域，其包含共有序列，如典型的TATA盒和CAAT盒，以及可能由creA蛋白调控葡萄糖的多个位点。推导的1926个氨基酸序列与构巢曲霉的FksAp相似度超过85%，与酿酒酵母的Fks1p和Fks2p相似度为71%。巴西副球孢子菌Fks1p的计算分析表明，其结构与跨膜蛋白FksAp相似，存在两个由疏水螺旋组成的结构域，这些结构域限制了细胞质内推定的高度亲水的催化结构域。
