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	Characterization of a sodium-regulated glutaminase from cyanobacterium synechocystis sp pcc 6803
	Zhou Jie1; Zhou JunXia1,2; Yang HaoMeng1; Yan ChengShi1; Huang Fang1
刊名	Science in china series c-life sciences
	2008-12-01
卷号	51期号:12页码:1066-1075
关键词	Cyanobacteria Synechocystis Putative glutaminase Enzyme activity Mutagenesis Salt tolerance
ISSN号	1006-9305
DOI	10.1007/s11427-008-0137-2
通讯作者	Huang fang(fhuang@ibcas.ac.cn)
英文摘要	Glutaminase is widely distributed among microorganisms and mammals with important functions. little is known regarding the biochemical properties and functions of the deamidating enzyme glutaminase in cyanobacteria. in this study a putative glutaminase encoded by gene slr2079 in synechocystis sp. pcc 6803 was investigated. the slr2079 was expressed as histidine-tagged fusion protein in escherichia coli. the purified protein possessed glutaminase activity, validating the functional assignment of the genomic annotation. the apparent k (m) value of the recombinant protein for glutamine was 26.6 +/- 0.9 mmol/l, which was comparable to that for some of other microbial glutaminases. analysis of the purified protein revealed a two-fold increase in catalytic activity in the presence of 1 mol/l na(+). moreover, the k (m) value was decreased to 12.2 +/- 1.9 mmol/l in the presence of na(+). these data demonstrate that the recombinant protein slr2079 is a glutaminase which is regulated by na(+) through increasing its affinity for substrate glutamine. the slr2079 gene was successfully disrupted in synechocystis by targeted mutagenesis and the delta slr2079 mutant strain was analyzed. no differences in cell growth and oxygen evolution rate were observed between delta slr2079 and the wild type under standard growth conditions, demonstrating slr2079 is not essential in synechocystis. under high salt stress condition, however, delta slr2079 cells grew 1.25-fold faster than wild-type cells. moreover, the photosynthetic oxygen evolution rate of delta slr2079 cells was higher than that of the wild-type. to further characterize this phenotype, a number of salt stress-related genes were analyzed by semi-quantitative rt-pcr. expression of gdhb and prc was enhanced and expression of desd and guaa was repressed in delta slr2079 compared to the wild type. in addition, expression of two key enzymes of ammonium assimilation in cyanobacteria, glutamine synthetase (gs) and glutamate synthase (gogat) was examined by semi-quantitative rt-pcr. expression of gogat was enhanced in delta slr2079 compared to the wild type while gs expression was unchanged. the results indicate that slr2079 functions in the salt stress response by regulating the expression of salt stress related genes and might not play a major role in glutamine breakdown in synechocystis.
WOS关键词	PHOSPHATE-ACTIVATED GLUTAMINASE ; MICROCOCCUS-LUTEUS K-3 ; SP STRAIN PCC-6803 ; SALT-STRESS ; AMMONIUM ASSIMILATION ; MOLECULAR-CLONING ; RAT ; PURIFICATION ; METABOLISM ; SEQUENCE
WOS研究方向	Life Sciences & Biomedicine - Other Topics
WOS类目	Biology
语种	英语
出版者	SCIENCE PRESS
WOS记录号	WOS:000261832500002
内容类型	期刊论文
URI标识	http://www.corc.org.cn/handle/1471x/2393196
专题	中国科学院大学
通讯作者	Huang Fang
作者单位	1.Chinese Acad Sci, Inst Bot, Key Lab Photosynthesis & Environm Mol Physiol, Beijing 100093, Peoples R China 2.Chinese Acad Sci, Grad Sch, Beijing 100039, Peoples R China
推荐引用方式 GB/T 7714	Zhou Jie,Zhou JunXia,Yang HaoMeng,et al. Characterization of a sodium-regulated glutaminase from cyanobacterium synechocystis sp pcc 6803[J]. Science in china series c-life sciences,2008,51(12):1066-1075.
APA	Zhou Jie,Zhou JunXia,Yang HaoMeng,Yan ChengShi,&Huang Fang.(2008).Characterization of a sodium-regulated glutaminase from cyanobacterium synechocystis sp pcc 6803.Science in china series c-life sciences,51(12),1066-1075.
MLA	Zhou Jie,et al."Characterization of a sodium-regulated glutaminase from cyanobacterium synechocystis sp pcc 6803".Science in china series c-life sciences 51.12(2008):1066-1075.

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