Alazi Ebru, Khosravi Claire, Homan Tim G, du Pré Saskia, Arentshorst Mark, Di Falco Marcos, Pham Thi T M, Peng Mao, Aguilar-Pontes Maria Victoria, Visser Jaap, Tsang Adrian, de Vries Ronald P, Ram Arthur F J
Molecular Microbiology and Biotechnology, Institute of Biology Leiden, Leiden University, The Netherlands.
Fungal Physiology, Westerdijk Fungal Biodiversity Institute, Utrecht University, The Netherlands.
FEBS Lett. 2017 May;591(10):1408-1418. doi: 10.1002/1873-3468.12654. Epub 2017 May 6.
In Aspergillus niger, the enzymes encoded by gaaA, gaaB, and gaaC catabolize d-galacturonic acid (GA) consecutively into l-galactonate, 2-keto-3-deoxy-l-galactonate, pyruvate, and l-glyceraldehyde, while GaaD converts l-glyceraldehyde to glycerol. Deletion of gaaB or gaaC results in severely impaired growth on GA and accumulation of l-galactonate and 2-keto-3-deoxy-l-galactonate, respectively. Expression levels of GA-responsive genes are specifically elevated in the ∆gaaC mutant on GA as compared to the reference strain and other GA catabolic pathway deletion mutants. This indicates that 2-keto-3-deoxy-l-galactonate is the inducer of genes required for GA utilization.
在黑曲霉中，由gaaA、gaaB和gaaC编码的酶依次将D-半乳糖醛酸（GA）分解代谢为L-半乳糖酸、2-酮-3-脱氧-L-半乳糖酸、丙酮酸和L-甘油醛，而GaaD则将L-甘油醛转化为甘油。gaaB或gaaC的缺失分别导致在GA上生长严重受损以及L-半乳糖酸和2-酮-3-脱氧-L-半乳糖酸的积累。与参考菌株和其他GA分解代谢途径缺失突变体相比，GA响应基因的表达水平在GA上的∆gaaC突变体中特异性升高。这表明2-酮-3-脱氧-L-半乳糖酸是GA利用所需基因的诱导物。
