PROSITE documentation PDOC51502 [for PROSITE entry PS51502]

Stress-response A/B barrel domain profile

The stress-response A/B barrel domain is found in a class of stress-response proteins in plants and in some bacterial fructose-bisphosphate aldolase. The stress-response A/B barrel domain forms a very stable dimer. This dimer belongs to the superfamily of dimeric α+β barrels in which the two β-sheets form a β-barrel. The two molecules in the dimer are related by a 2-fold axis parallel to helix H1 and β-strands B3 and B4. The outer surface of the β-sheets of the two molecules forms a β-barrel-like structure defining a central pore. The function of the stress-response A/B barrel domain is unknown [1,2,3].

The stress-response A/B barrel domain has an α/β structure consisting of a four-stranded antiparallel β-sheet and three α-helices, arranged in a β-α-β-β-α-α-β topology (see <PDB:1Q4R>). Two sheets join at their edges to form an oblong β-barrel, flanked by four helices on each of the opposing faces. C-terminal residues extending from the β4 strand of each monomer wrap around and connect with the β2 strand and α1 helix of the opposing monomer to form the dimer interface [1,2,3].

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) (also known as Pop3 in other Populus species), a thermostable stress-responsive protein.
• Pseudomonas hydrogenothermophila fructose 1,6-bisphosphate aldolase (cbbA).

The profile we developed covers the entire stress-response A/B barrel domain.