¶ … structure of Jann_2411( DUF14790) from Jannaschia sp at 1.45 A resolution reveals a new fold ( the ABATE domain) and suggests its possible role as transcription regulator" The purpose of this study was to resolve the structure of the protein Jann_2411 and relate its structure to the functional properties of the protein. The researchers determined the structure using the method of x-ray crystallography (multiple wavelength anomalous diffraction) and structural analysis of the protein revealed it to be a putative stress-related transcription factor.

Jann_2411 has a molecular weight of 20.7 kDa (residues 1-187) and a calculated isoelectric point of 6.6 and its crystal structure was determined using the semiautomated high-throughput pipeline of the Joint Center for Structural Genomics. Structural analysis revealed a two domain organization with the N-terminal domain consisting of a new fold called ABATE (Alpha-beta hairpin and Alpha TandEm) domain and the C-terminal domain forming a treble-clef zinc finger after a characteristic conserved sequence. Jan_2411 forms a dimer that binds DNA forming a putative stress-related transcription factor for which the ABATE domain is implicated.

However, the structure shows that Jann_2411 is actually comprised of two domains. The first domain (residues 1 -- 142) can be visualized as two subdomains (H2 -- H4, 1 -- 2 and H5 -- H7, 3 -- 4) that share similar topology and secondary-structure elements, namely a helix -- -hairpin -- helix motif (H2-1-2-H3 in the first subdomain; H6-3- 4-H7 in the second subdomain), with an additional helix (H4 from the first subdomain and H5 from the second subdomain) linking the two motifs. The researchers have therefore named this region the ABATE domain, representing the Alpha-Beta-hairpin-Alpha TandEm motif.
The second domain (residues 143 -- 187; H8, 5 -- 6, H9) forms a treble-clef zinc finger. The zinc ion is coordinated by two cysteines (Cys147 and Cys152) from a loop termed the zinc knuckle, located between the strands of the third -hairpin (5 -- 6), and two cysteines from the N-terminus of helix H9 (Cys168 and Cys172). This arrangement of zinc-coordinating residues is typical of treble-clef zinc fingers. Other strictly conserved residues in this domain include Asp158 and Arg175. A…