Functional analysis of ∆98∆-IFAB, a β barrel variant

GUERBI MX; RODRIGUEZ SAWICKI, L; FALOMIR LOCKHART LJ; CURTO, LUCRECIA; FRANCHINI GR; DELFINO, JM; CÓRSICO B

La Plata

Congreso; XXXV Reunión Anual de la SAB; 2008

Sociedad Argentina de Biofísica

Fatty acid binding proteins (FABPs) share a similar β-barrel fold that resembles a clamshell. This β-barrel, which encloses the ligand binding cavity, consists of two five-stranded β-sheets arranged in nearly orthogonal orientation. All β strands are connected by loops with the exception of strands A and B, where an intervening helix-turn-helix motif appears. In particular, IFABP is an intracellular protein whose function is still uncertain. Δ98Δ (fragment 29-126 of IFABP) was obtained either in its recombinant form or by limited proteolysis with clostripain of Holo-IFABP. Previous results indicate that the helical domain is not necessary to preserve the general topology of IFABP, and cumulative evidences show that Δ98Δ adopts a monomeric, stable state in solution, with compact core and loose periphery [4] . However, it is accepted that the portal region is involved in ligand binding and release [1],[2],[3] , specially through the protein to membrane interaction. Here, we present the functional characterization of Δ98Δ, the shortest form of IFABP described so far preserving binding activity.