SBT1.7 Antibody
Description
SBT1.7: A Subtilase Enzyme in Plant Immunity
SBT1.7 (Subtilisin-like protease) is a secreted subtilase in Arabidopsis that plays a critical role in processing bacterial flagellin to release immunogenic peptides, such as flg22. This process is essential for triggering pattern-triggered immunity (PTI) against pathogens .
Mechanism of Action
SBT1.7 and SBT5.2 cooperatively process flagellin to balance immune activation:
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Cleavage at Asn 39-Ser 40: Inactivates flg22 by disrupting its immunogenic epitope .
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C-terminal Processing: SBT1.7 specifically targets the C-terminal region of flagellin, distinguishing it from SBT5.2 .
Experimental Evidence
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Nano-LC–MS/MS Analysis: Flagellin digested with SBT1.7-His showed cleavage at Asn 207-Ser 208, Gln 217-Asn 218, and Gln 228-Asn 229 .
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Mutant Studies: In sbt5.2 sbt1.7 double mutants, C-terminal cleavage of flg22 decreased by 96% compared to wild-type plants .
Functional Interplay with SBT5.2
SBT1.7 and SBT5.2 exhibit overlapping but distinct substrate specificities:
| Cleavage Site | SBT5.2 Preference | SBT1.7 Preference |
|---|---|---|
| Ala 51-Thr 52 | Primary site for flg22 release | Secondary site |
| Asn 207-Ser 208 | Not cleaved | Primary site |
| Gln 217-Asn 218 | Not cleaved | Secondary site |
Synergistic Role:
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SBT5.2 primarily releases flg22, while SBT1.7 modulates its stability by cleaving it internally .
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Combined activity ensures spatial-temporal control of PTI, preventing excessive immune responses .
Experimental Tools and Antibodies
While no commercial SBT1.7-specific antibodies are documented in the provided sources, anti-His-tag antibodies were used to detect recombinant SBT1.7-His in Western blots . Researchers may develop custom anti-SBT1.7 antibodies for:
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Enzyme Detection: Quantifying SBT1.7 protein levels in apoplastic fluid.
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Localization Studies: Tracking SBT1.7 distribution in plant tissues.
Research Gaps and Future Directions
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Antibody Development: No peer-reviewed studies describe anti-SBT1.7 antibodies. Potential applications include immunoprecipitation or ELISA.
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Evolutionary Conservation: SBT1.7 homologs in other plants (e.g., tomato) show similar flagellin-processing activity , suggesting conserved roles.
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Pathogen Countermeasures: Bacteria may evolve flagellin variants resistant to SBT1.7/SBT5.2 cleavage to evade detection.
Product Specs
Constituents: 50% Glycerol, 0.01M PBS, pH 7.4
Target Background
- Another regulator of PME activity in seed coat epidermal cells is the subtilisin-like Ser protease SBT1.7. This protease acts on different PMEs, as a pmei6 sbt1.7 mutant showed an additive phenotype. PMID: 23362209
Q&A
FAQs for SBT1.7 Antibody in Academic Research
Advanced Research Questions
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How to resolve discrepancies in SBT1.7 localization studies across publications?
Conflicting localization data may arise from:-
Antibody specificity: Validate antibodies using knockout lines (see FAQ #2).
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Tissue-specific expression: Perform qRT-PCR or promoter-GUS fusions to confirm expression patterns.
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Methodological variability: Standardize protocols for subcellular fractionation and imaging (e.g., confocal microscopy with organelle markers) .
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Can SBT1.7 antibodies be repurposed for studying homologous proteases in other plant species?
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Sequence alignment: Compare SBT1.7 epitopes with homologs in target species (e.g., Nicotiana benthamiana).
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Cross-reactivity testing: Use Western blotting against protein extracts from non-Arabidopsis species.
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Functional complementation: Express SBT1.7 homologs in Arabidopsis sbt1.7 mutants to assess rescue of ROS phenotypes .
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What statistical approaches are suitable for analyzing SBT1.7 activity in high-throughput screens?
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Dose-response curves: Fit data to Michaelis-Menten kinetics to calculate and .
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Machine learning: Train classifiers to predict protease activity based on substrate sequence features.
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Multivariate analysis: Use principal component analysis (PCA) to disentangle SBT1.7-specific effects from background noise in transcriptomic/proteomic datasets .
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Data Contradiction & Reproducibility
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How to address inconsistent reports of SBT1.7’s role in pathogen resistance?
Table 1: Key Validation Metrics for SBT1.7 Antibodies
| Application | Validation Criteria | Recommended Controls |
|---|---|---|
| Western blotting | Band at ~75 kDa in WT, absent in sbt1.7⁻ | Knockout lysate, pre-immune serum |
| Immunoprecipitation | Co-precipitation of known interactors | IgG-isotype control, empty beads |
| Activity assays | Loss of proteolytic function in mutants | Catalytic dead SBT1.7 (S478A) |
Table 2: Common Pitfalls in SBT1.7 Research
| Issue | Solution |
|---|---|
| Cross-reactivity with SBT5.2 | Use double mutants (sbt1.7/sbt5.2) for phenotyping |
| Low antibody sensitivity | Optimize blocking buffers (e.g., 5% BSA + 0.1% Tween-20) |
| Epitope masking in fixed tissues | Try antigen retrieval with citrate buffer (pH 6.0) |
