Solution structure of a BolA-like protein from Mus musculus

Abstract

The BolA-like proteins are widely conserved from prokaryotes to eukaryotes. The BolA-like proteins seem to be involved in cell proliferation or cell-cycle regulation, but the molecular function is still unknown. Here we determined the structure of a mouse BolA-like protein. The overall topology is alphabetabetaalphaalphabetaalpha, in which beta(1) and beta(2) are antiparallel, and beta(3) is parallel to beta(2). This fold is similar to the class II KH fold, except for the absence of the GXXG loop, which is well conserved in the KH fold. The conserved residues in the BolA-like proteins are assembled on the one side of the protein.

Figure 1.

(A) Multiple sequence alignment of the BolA2 subfamily. Highlighted and shaded residues indicate identical and similar residues, respectively. Mm: BolA2 from Mus musculus. Hs: My016 from Homo sapiens. Dm: CG16804-PB from Drosophila melanogaster. Ag: agCP4532 from Anopheles gambiae. Sp: SPAC8C9.11 from Schizosaccharomyces pombe. The multiple alignment was achieved with CLUSTAL_X (Thompson et al. 1997). The secondary structures of the mouse BolA2 are indicated at the top of the alignment. (B) Ribbon diagram of BolA2. (C) Class II KH domains of ribosomal protein S3 (top, PDB ID: 1J5E) and Era GTPase (bottom, PDB ID: 1EGA). Each class II KH domain is colored in the rainbow order, from red (N terminus) to blue (C terminus).

Figure 2.

(A) The conserved residues on the surface of the mouse BolA2. The identical and the similar residues defined in Figure 1A ▶ are colored dark blue and light blue, respectively. The right panel is viewed from the opposite side of the left panel. (B) The surface electrostatic potential of BolA2. (C) Ribbon diagram in the same orientation as A and B. The HTH motif is indicated by the blue circle.