Dabb

Stress responsive A/B Barrel Domain
Dabb
SMART accession number:SM00886
Description: The function of this domain is unknown, but it is upregulated in response to salt stress in Populus balsamifera (balsam poplar). It is also found at the C-terminus of a fructose 1,6-bisphosphate aldolase from Hydrogenophilus thermoluteolus.It is found in the pA01 plasmid, which encodes genes for molybdopterin uptake and degradation of plant alkaloid nicotine. The structure of one has been solved and the domain forms an alpha-beta barrel dimer. Although there is a clear duplication within the domain it is not obviously detectable in the sequence.
Interpro abstract (IPR013097):

The stress-response A/B barrel domain is found in a class of stress-response proteins in plants. It is also found in some bacterial fructose-bisphosphate aldolase such as at the C terminus of a fructose 1,6-bisphosphate aldolase from Hydrogenophilus thermoluteolus (Q9ZA13) [(PUBMED:10705449)]. Q93NG5 is found in the pA01 plasmid, which encodes genes for molybdopterin uptake and degradation of plant alkaloid nicotine.

The stress-response A/B barrel domain forms a very stable dimer. This dimer belongs to the superfamily of dimeric alpha+beta barrels in which the two beta-sheets form a beta-barrel. The two molecules in the dimer are related by a 2-fold axis parallel to helix H1 and beta-strands B3 and B4. C-terminal residues extending from the beta4 strand of each monomer wrap around and connect with the beta2 strand and alpha1 helix of the opposing monomer to form the dimer interface [(PUBMED:15364906), (PUBMED:15213437), (PUBMED:15371455)].The outer surface of the beta-sheets of the two molecules forms a beta-barrel-like structure defining a central pore.

The function of the stress-response A/B barrel domain is unknown [(PUBMED:15364906), (PUBMED:15213437), (PUBMED:15371455)], but it is upregulated in response to salt stress in Populus balsamifera (balsam poplar) [(PUBMED:14704136)].

Some proteins known to contain a stress response A/B barrel domain are listed below:

- Arabidopsis thaliana At3g17210

- Arabidopsis thaliana At5g22580

-Populus tremula stable protein 1 (SP-1)(Populus species), a thermostable stress-responsive protein.

- Pseudomonas hydrogenothermophila fructose 1,6-bisphosphate aldolase (cbbA).

The structure of one of these proteins has been solved (Q9LUV2) and the domain forms an alpha-beta barrel dimer [(PUBMED:14872131)].

Family alignment:
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There are 2304 Dabb domains in 2238 proteins in SMART's nrdb database.

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