Hayashi N R, Terazono K, Kodama T, Igarashi Y
Department of Biotechnology, University of Tokyo, Japan.
Biosci Biotechnol Biochem. 2000 Jan;64(1):61-71. doi: 10.1271/bbb.64.61.
Four genes, cbbO, cbbY, cbbA, and the pyruvate kinase gene (pyk), were found downstream of ribulose 1,5-bisphosphate carboxylase/oxygenase (RubisCO) genes, cbbLS, from a thermophilic hydrogen-oxidizing bacterium, Hydrogenophilus thermoluteolus (formerly Pseudomonas hydrogenothermophila). cbbO was similar to norD in the denitrification gene cluster, and cbbY was similar to cbbY from other autotrophic bacteria. cbbA encoded fructose 1,6-bisphosphate aldolase (FBP aldolase); however, CbbA was little similar to other CbbA proteins. When CbbA was overexpressed in Escherichia coli, overproduction of CbbA was detected by SDS-PAGE. However, the cell extract had slightly higher activity than a cell extract of E. coli without cbbA. Phylogenetic analysis showed class II FBP aldolase divided into classes IIA and IIB, and that CbbA from H. thermoluteolus was in class IIA. Activities of RubisCO and FBP aldolase were examined under autotrophic, mixotrophic, and heterotrophic conditions. The activities of the two enzymes were regulated independently.
从嗜热氢氧化细菌嗜热栖热菌（以前称为嗜热氢假单胞菌）中发现，四个基因，即cbbO、cbbY、cbbA和丙酮酸激酶基因（pyk），位于1,5-二磷酸核酮糖羧化酶/加氧酶（RubisCO）基因cbbLS的下游。cbbO与反硝化基因簇中的norD相似，cbbY与其他自养细菌中的cbbY相似。cbbA编码1,6-二磷酸果糖醛缩酶（FBP醛缩酶）；然而，CbbA与其他CbbA蛋白几乎没有相似性。当CbbA在大肠杆菌中过表达时，通过SDS-PAGE检测到CbbA的过量产生。然而，细胞提取物的活性略高于不含cbbA的大肠杆菌细胞提取物。系统发育分析表明，II类FBP醛缩酶分为IIA和IIB类，嗜热栖热菌的CbbA属于IIA类。在自养、兼养和异养条件下检测了RubisCO和FBP醛缩酶的活性。这两种酶的活性是独立调节的。
