Complementation cloning and sequence analysis of the Chlamydomonas reinhardtii hemL gene encoding glutamate-1-semialdehyde aminotransferase

Conference · Sat May 01 00:00:00 EDT 1993 · Plant Physiology; (United States)

OSTI ID:6281928

Matters, G L; Beale, S I ^[1]

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1. Brown Univ., Providence, RI (United States)

Glutamate-1-semialdehyde amino-transferase (GSAT) catalyzes formation of the tetrapyrrole precursor, [delta]-aminolevulinic acid. GSAT is encoded by the hemL gene. A Chlamydomonas reinhardtii hemL cDNA was selected from a vegetative stage expression library by complementation of Escherichia coli hemL mutant GE 1377. In vitro GSAT activity was ten-fold higher in an extract of the complemented hemL cells than in an extract of uncomplemented mutant cells. The complementing cDNA is 2010 bp long and includes 591 bp of 3' noncoding DNA and an estimated 27 bp of 5' noncoding DNA. The coding region includes the sequence for a putative 30-amino acid chloroplast transit peptide and a 433-amino acid mature protein. The mature protein deduced from the Chlamydomonas cDNA sequence has a molecular weight of 45,880, compared to the value of 43,000 reported for purified Chlamydomonas GSAT (d. Jahn et al., 1991, J. Biol. Chem. 266:161-167). The deduced peptide is 74% identical to Synechococcus GSAT, 70% identical to barley GSAT and 66% identical to tobacco GSAT. The putative pyridoxal binding region has the sequence TTMGKVIGG, which differs somewhat from those reported for other aminotransferases. The deduced putative chloroplast transit peptide has recognizable similarity to barley GSAT transit peptide. Southern analysis of genomic DNA from Chlamydomonas strain CC124, using the cDNA as a probe, indicates that GSAT is probably encoded by a single gene.

• OSTI ID: 6281928
• Report Number(s): CONF-9307119-; CODEN: PLPHAY
• Journal Information: Plant Physiology; (United States), Vol. 102:1; Conference: 1993 joint annual meeting of the American Society of Plant Physiologists (ASPP) and the Canadian Society of Plant Physiologists (CSPP), Minneapolis, MN (United States), 31 Jul - 4 Aug 1993; ISSN 0032-0889
• Country of Publication: United States
• Language: English

Related Subjects

59 BASIC BIOLOGICAL SCIENCES
AMINOTRANSFERASES
DNA-CLONING
CHLAMYDOMONAS
DNA SEQUENCING
AMINOLEVULINIC ACID
BARLEY
ESCHERICHIA COLI
GENES
TOBACCO
ALGAE
AMINO ACIDS
BACTERIA
CARBOXYLIC ACIDS
CEREALS
CHLOROPHYCOTA
CLONING
DNA HYBRIDIZATION
ENZYMES
GRAMINEAE
HYBRIDIZATION
LILIOPSIDA
MAGNOLIOPHYTA
MICROORGANISMS
NITROGEN TRANSFERASES
ORGANIC ACIDS
ORGANIC COMPOUNDS
PLANTS
PROTEINS
STRUCTURAL CHEMICAL ANALYSIS
TRANSFERASES
UNICELLULAR ALGAE
550400* - Genetics