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Literature summary for 2.1.1.280 extracted from
- Identification and functional characterization of a novel selenocysteine methyltransferase from Brassica juncea L. (2019), J. Exp. Bot., 70, 6401-6416 .
Application
| Application | Comment | Organism |
|---|---|---|
| agriculture | Brassica juncea SMT demonstrates its potential applications in crop MeSeCys biofortification and phytoremediation of Se pollution | Brassica juncea |
Cloned(Commentary)
| Cloned (Comment) | Organism |
|---|---|
| gene SMT, DNA and amino acid sequence determination and analysis, sequence comparisons and phylogenetic analysis and tree, recombinant expression of GFP-tagged enzyme under control of 35S promoter in Nicotiana tabacum, quantitative real-time PCR enzyme expression analysis | Brassica juncea |
Protein Variants
| Protein Variants | Comment | Organism |
|---|---|---|
| additional information | overexpression of BjSMT in tobacco substantially enhances tolerance to selenite stress manifested as significantly higher fresh weight, plant height, and chlorophyll content than control plants. Transgenic plants exhibited low glutathione peroxidase activity in response to a lower dose of selenite stress (with a higher dose of selenite stress resulting in a high activity response) compared with the controls. The BjSMT-transformed tobacco plants accumulate a high level of Se upon selenite stress, and the plants also have significantly increased MeSeCys production potential in their leaves | Brassica juncea |
Metals/Ions
| Metals/Ions | Comment | Organism | Structure |
|---|---|---|---|
| Zn2+ | the presence of the conserved amino acids in BjSMT at positions Cys248, Cys315, and Cys316 suggests that BjSMT may also coordinate the binding of Zn2+ | Brassica juncea |  |
Natural Substrates/ Products (Substrates)
| Natural Substrates | Organism | Comment (Nat. Sub.) | Natural Products | Comment (Nat. Pro.) | Rev. | Reac. |
|---|---|---|---|---|---|---|
| S-methyl-L-methionine + L-homocysteine | Brassica juncea | - |
L-methionine + S-methyl-L-homocysteine | - |
? | |
| S-methyl-L-methionine + L-selenocysteine | Brassica juncea | - |
L-methionine + Se-methyl-L-selenocysteine | - |
? | |
Organism
| Organism | UniProt | Comment | Textmining |
|---|---|---|---|
| Brassica juncea | - |
- |
- |
Source Tissue
| Source Tissue | Comment | Organism | Textmining |
|---|---|---|---|
| leaf | - |
Brassica juncea | - |
| additional information | semiquantitative RT-PCR expression analysis of BjSMT transcript accumulation in leaves and roots of Indian mustard plants supplied with 0.04 mM Na2SeO4, 0.04 mM Na2SeO3, and 0.001 mM MgSO4 in the medium, overview | Brassica juncea | - |
| root | - |
Brassica juncea | - |
| seedling | - |
Brassica juncea | - |
Substrates and Products (Substrate)
| Substrates | Comment Substrates | Organism | Products | Comment (Products) | Rev. | Reac. |
|---|---|---|---|---|---|---|
| S-methyl-L-methionine + L-homocysteine | - |
Brassica juncea | L-methionine + S-methyl-L-homocysteine | - |
? | |
| S-methyl-L-methionine + L-selenocysteine | - |
Brassica juncea | L-methionine + Se-methyl-L-selenocysteine | - |
? | |
Synonyms
| Synonyms | Comment | Organism |
|---|---|---|
| BjSMT | - |
Brassica juncea |
| selenocysteine methyltransferase | - |
Brassica juncea |
| SMT | - |
Brassica juncea |
Expression
| Organism | Comment | Expression |
|---|---|---|
| Brassica juncea | BjSMT responds to selenite [Se(IV)] and selenate [Se(VI)] stress in Brassica juncea. BjSMT expression is nearly undetectable in the Brassica juncea plant without Se exposure, but in the plant leaves it can be rapidly and significantly upregulated upon a low level of selenite stress, and enormously upregulated upon selenate treatment | up |
General Information
| General Information | Comment | Organism |
|---|---|---|
| malfunction | overexpression of BjSMT in tobacco substantially enhances tolerance to selenite stress manifested as significantly higher fresh weight, plant height, and chlorophyll content than control plants. The BjSMT-transformed tobacco plants accumulate a high level of Se upon selenite stress, and the plants also have significantly increased MeSeCys production potential in their leaves. The enzyme is highly induced by selenite and especially selenate. BjSMT overexpressing plants maintain a higher level of GSH-Px activity and chlorophyll content under severe selenite treatment | Brassica juncea |
| additional information | the post-secondary structure assembled by conserved Cys207, Cys272, and Cys273 residues is believed to form such a geometrical catalytic pocket which will position the sulfur group of L-homocysteine in close proximity to Thr147, responsible for methyl group transfer by donating a hydrogen bond | Brassica juncea |
| physiological function | plants can easily absorb and assimilate Se in the form of selenate and selenite through sulfur transport proteins and metabolic pathways and remove it by converting it into volatilized methylated forms. The Se substitution of S in proteins can destroy the molecular function of these proteins, so an increased level of Se is toxic to most organisms. In plants,selenates are reduced and assimilated to organic Se which can be converted to methylselenocysteine (MeSeCys) in addition to selenocysteine (SeCys), selenomethionine (SeMet), and dimethylselenide (DMSe). Selenocysteine methyltransferase (SMT) is the key enzyme responsible for Se-methylselenocysteine (MeSeCys) formation. Brassica juncea is a selenium accumulator. BjSMT also possesses a conserved Thr187 which is involved in transferring a methyl group to L-homocysteine (HoCys) by donating a hydrogen bond, suggesting that BjSMT can methylate both HoCys and SeCys substrates | Brassica juncea |
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Release 2023.1 (January 2023)
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