SOBER1 is an enzyme that catalyzes the biochemical reaction of deacetylation.[1] The SOBER (Suppressor of AvrBsT-elicited resistance) 1 protein is conserved in plants and it suppresses the plant's ability to carry out the hypersensitive response against infection by certain pathogenic effector proteins from the YopJ family.[2] SOBER1 belongs to the protein superfamily of α/β hydrolases and possesses a canonical serine/histidine/aspartate catalytic triad to carry out the deacetylation reaction. There have been contradicting reports about SOBER1's potential phospholipase activity, with one study claiming phospholipase A2 activity of the protein[3] and another study being unable to reproduce this result.[1]

Crystal structure of Arabidopsis thaliana SOBER1, PDB code 6avv. Alpha helices are in red, beta strands in gold, catalytic site residues in black.
Identifiers
SymbolSOBER1
InterProIPR029058
CATH6avv
SCOP26avv / SCOPe / SUPFAM

Relationship to acyl-protein thioesterases

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Members of the SOBER1 family are considered closely related to acyl-protein thioesterases, judged by their protein structure.[2] However, a change in their amino acid sequence renders SOBER1's biochemical properties into a deacetylase; in particular the hydrophobic tunnel, which is found in acyl-protein thioesterases, is impaired by additional amino acids in the lid structure of SOBER1, creating a new surface for binding of the acetyl group.[1]

 
Mechanism of SOBER1 deacetylase function, highlighting the additional amino acids in the protein lid. Nature Communications 8(1):2201, Creative Commons Attribution 4.0 International License, https://creativecommons.org/licenses/by/4.0/

Targets

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So far, the following proteins have been identified as SOBER1 targets: AvrBsT; ACIP1.

See also

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References

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  1. ^ a b c Bürger M, Willige BC, Chory J (December 2017). "A hydrophobic anchor mechanism defines a deacetylase family that suppresses host response against YopJ effectors". Nature Communications. 8 (1): 2201. Bibcode:2017NatCo...8.2201B. doi:10.1038/s41467-017-02347-w. PMC 5736716. PMID 29259199.
  2. ^ a b Cunnac S, Wilson A, Nuwer J, Kirik A, Baranage G, Mudgett MB (February 2007). "A conserved carboxylesterase is a SUPPRESSOR OF AVRBST-ELICITED RESISTANCE in Arabidopsis". The Plant Cell. 19 (2): 688–705. doi:10.1105/tpc.106.048710. PMC 1867326. PMID 17293566.
  3. ^ Kirik A, Mudgett MB (December 2009). "SOBER1 phospholipase activity suppresses phosphatidic acid accumulation and plant immunity in response to bacterial effector AvrBsT". Proceedings of the National Academy of Sciences of the United States of America. 106 (48): 20532–7. Bibcode:2009PNAS..10620532K. doi:10.1073/pnas.0903859106. PMC 2787154. PMID 19918071.