Newman J, Karakaya H, Scanlan D J, Mann N H
Department of Biological Sciences, University of Warwick, Coventry, UK.
FEMS Microbiol Lett. 1995 Nov 1;133(1-2):187-93. doi: 10.1111/j.1574-6968.1995.tb07882.x.
The region of the genome encoding the glucose-6-phosphate dehydrogenase gene zwf was analysed in a unicellular cyanobacterium, Synechococcus sp. PCC 7942, and a filamentous, heterocystous cyanobacterium, Anabaena sp. PCC 7120. Comparison of cyanobacterial zwf sequences revealed the presence of two absolutely conserved cysteine residues which may be implicated in the light/dark control of enzyme activity. The presence in both strains of a gene fbp, encoding fructose-1,6-bisphosphatase, upstream from zwf strongly suggests that the oxidative pentose phosphate pathway in these organisms may function to completely oxidize glucose 6-phosphate to CO2. The amino acid sequence of fructose-1,6-bisphosphatase does not support the idea of its light activation by a thiol/disulfide exchange mechanism. In the case of Anabaena sp. PCC 7120, the tal gene, encoding transaldolase, lies between zwf and fbp.
对单细胞蓝细菌聚球藻属（Synechococcus sp.）PCC 7942和丝状、异形胞蓝细菌鱼腥藻属（Anabaena sp.）PCC 7120中编码葡萄糖-6-磷酸脱氢酶基因zwf的基因组区域进行了分析。蓝细菌zwf序列的比较显示存在两个绝对保守的半胱氨酸残基，这可能与酶活性的光/暗控制有关。在zwf上游的两个菌株中都存在编码果糖-1,6-二磷酸酶的fbp基因，这强烈表明这些生物体中的氧化戊糖磷酸途径可能起到将6-磷酸葡萄糖完全氧化为CO₂的作用。果糖-1,6-二磷酸酶的氨基酸序列不支持其通过硫醇/二硫键交换机制进行光激活的观点。在鱼腥藻属PCC 7120中，编码转醛醇酶的tal基因位于zwf和fbp之间。
