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Structural and Functional Assays of AtTLP18.3 Identify Its Novel Acid Phosphatase Activity in Thylakoid Lumen
- Source :
- Plant Physiology. 157:1015-1025
- Publication Year :
- 2011
- Publisher :
- Oxford University Press (OUP), 2011.
-
Abstract
- The membrane protein AtTLP18.3 of Arabidopsis (Arabidopsis thaliana) contains a domain of unknown function, DUF477; it forms a polysome with photosynthetic apparatuses in the thylakoid lumen. To explore the molecular function of AtTLP18.3, we resolved its crystal structures with residues 83 to 260, the DUF477 only, and performed a series of biochemical analyses to discover its function. The gene expression of AtTLP18.3 followed a circadian rhythm. X-ray crystallography revealed the folding of AtTLP18.3 as a three-layer sandwich with three α-helices in the upper layer, four β-sheets in the middle layer, and two α-helices in the lower layer, which resembles a Rossmann fold. Structural comparison suggested that AtTLP18.3 might be a phosphatase. The enzymatic activity of AtTLP18.3 was further confirmed by phosphatase assay with various substrates (e.g. p-nitrophenyl phosphate, 6,8-difluoro-4-methylumbelliferyl phosphate, O-phospho-l-serine, and several synthetic phosphopeptides). Furthermore, we obtained the structure of AtTLP18.3 in complex with O-phospho-l-serine to identify the binding site of AtTLP18.3. Our structural and biochemical studies revealed that AtTLP18.3 has the molecular function of a novel acid phosphatase in the thylakoid lumen. DUF477 is accordingly renamed the thylakoid acid phosphatase domain.
- Subjects :
- Models, Molecular
Rossmann fold
Physiology
Acid Phosphatase
Molecular Sequence Data
Phosphatase
Arabidopsis
Biochemical Processes and Macromolecular Structures
Plant Science
Regulatory Sequences, Nucleic Acid
Crystallography, X-Ray
Cyanobacteria
Thylakoids
Protein Structure, Secondary
Substrate Specificity
Phosphoserine
Gene Expression Regulation, Plant
Polysome
Genetics
Arabidopsis thaliana
Amino Acid Sequence
RNA, Messenger
Binding site
Conserved Sequence
Enzyme Assays
biology
Arabidopsis Proteins
Acid phosphatase
biology.organism_classification
Circadian Rhythm
Protein Structure, Tertiary
Kinetics
Biochemistry
Structural Homology, Protein
Thylakoid
biology.protein
Sequence Alignment
Subjects
Details
- ISSN :
- 15322548
- Volume :
- 157
- Database :
- OpenAIRE
- Journal :
- Plant Physiology
- Accession number :
- edsair.doi.dedup.....47242a7045c0fc5663e461131bf657aa