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Role of OsHAL3 Protein, a Putative 4′-Phosphopantothenoylcysteine Decarboxylase in Rice

Ning Zhang1,2, Xuechen Wang1, and Jia Chen1*

1State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, Beijing 100094, China; fax: +86-10-6273-3491; E-mail: chenja@public.bta.net.cn; xcwang@cau.edu.cn

2Laboratory of Development Biology, Biological Science and Technology College, Shenyang Agricultural University, Shengyang 110161, China; E-mail: zhangning_66@163.com

* To whom correspondence should be addressed.

Received April 17, 2008; Revision received June 2, 2008
In this study, we cloned the OsHAL3 gene from rice Oryza sativa. Alignment analysis revealed that OsHAL3 has a high sequence identity to Dfp protein in Escherichia coli and AtHAL3a protein in Arabidopsis thaliana, which have 4′-phosphopantothenoylcysteine decarboxylase (PPC-DC) activity. OsHAL3 can complement mutation in the E. coli dfp gene encoding PPC-DC, so that the mutant strains with OsHAL3 can grow on rich media at 42°C and on VB minimal media at 30°C. Complementation tests with point mutations of OsHAL3 suggested that the conserved Cys176 residue of OsHAL3 is a key active-site residue. The mutant OsHAL3 G180A has a partly reduced activity. Related mRNA-level analysis showed that the OsHAL3 gene is induced by calcium pantothenate in rice.
KEY WORDS: OsHAL3, 4′-phosphopantothenoylcysteine decarboxylase, coenzyme A, rice

DOI: 10.1134/S000629790901009X