Linked Life Data

12631323

Source:http://linkedlifedata.com/resource/pubmed/id/12631323

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
6
pubmed:dateCreated
2003-3-12
pubmed:abstractText
In the photorespiratory process, peroxisomal glutamate:glyoxylate aminotransferase (GGAT) catalyzes the reaction of glutamate and glyoxylate to 2-oxoglutarate and glycine. Although GGAT has been assumed to play important roles for the transamination in photorespiratory carbon cycles, the gene encoding GGAT has not been identified. Here, we report that an alanine:2-oxoglutarate aminotransferase (AOAT)-like protein functions as GGAT in peroxisomes. Arabidopsis has four genes encoding AOAT-like proteins and two of them (namely AOAT1 and AOAT2) contain peroxisomal targeting signal 1 (PTS1). The expression analysis of mRNA encoding AOATs and EST information suggested that AOAT1 was the major protein in green leaves. When AOAT1 fused to green fluorescent protein (GFP) was expressed in BY-2 cells, it was found to be localized to peroxisomes depending on PTS1. By screening of Arabidopsis T-DNA insertion lines, an AOAT1 knockout line (aoat1-1) was isolated. The activity of GGAT and alanine:glyoxylate aminotransferase (AGAT) in the above-ground tissues of aoat1-1 was reduced drastically and, AOAT and glutamate:pyruvate aminotransferase (GPAT) activity also decreased. Peroxisomal GGAT was detected in the wild type but not in aoat1-1. The growth rate was repressed in aoat1-1 grown under high irradiation or without sugar, though differences were slight in aoat1-1 grown under low irradiation, high-CO2 (0.3%) or high-sugar (3% sucrose) conditions. These phenotypes resembled those of photorespiration-deficient mutants. Glutamate levels increased and serine levels decreased in aoat1-1 grown in normal air conditions. Based on these results, it was concluded that AOAT1 is targeted to peroxisomes, functions as a photorespiratory GGAT, plays a markedly important role for plant growth and the metabolism of amino acids.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Mar
pubmed:issn
0960-7412
pubmed:author
pubmed:issnType
Print
pubmed:volume
33
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
975-87
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed-meshheading:12631323-Alanine Transaminase, pubmed-meshheading:12631323-Amino Acid Sequence, pubmed-meshheading:12631323-Arabidopsis, pubmed-meshheading:12631323-Base Sequence, pubmed-meshheading:12631323-Carbohydrate Metabolism, pubmed-meshheading:12631323-Carbon Dioxide, pubmed-meshheading:12631323-Cell Respiration, pubmed-meshheading:12631323-Cloning, Molecular, pubmed-meshheading:12631323-Gene Deletion, pubmed-meshheading:12631323-Gene Expression Regulation, Plant, pubmed-meshheading:12631323-Genes, Plant, pubmed-meshheading:12631323-Glutamic Acid, pubmed-meshheading:12631323-Glyoxylates, pubmed-meshheading:12631323-Light, pubmed-meshheading:12631323-Molecular Sequence Data, pubmed-meshheading:12631323-Peroxisomes, pubmed-meshheading:12631323-Photosynthesis, pubmed-meshheading:12631323-Photosynthetic Reaction Center Complex Proteins, pubmed-meshheading:12631323-Protein Sorting Signals, pubmed-meshheading:12631323-Sequence Alignment, pubmed-meshheading:12631323-Transaminases
pubmed:year
2003
pubmed:articleTitle
Identification of photorespiratory glutamate:glyoxylate aminotransferase (GGAT) gene in Arabidopsis.
pubmed:affiliation
Institute of Life Sciences, Ajinomoto Co., Inc., 1-1 Suzuki-cho, Kawasaki 210-8681, Japan.
pubmed:publicationType
Journal Article