This domain is found in MSMEG_5817 gene product from M. smegmatis. It has been shown to be vital for mycobacterial survival within host macrophages. Crystal structure revealed a Rossmann-like fold alpha/beta two-layer sandwich forming a highly hydrophobic interface cavity and with high structural homology to the SCP family. Hence, it has been suggested that this domain may be involved in the interaction of apolar ligands through its hydrophobic cavity. Alanine-scanning mutagenesis of the hydrophobic cavity of MSMEG_5817 protein demonstrated that the conserved Val82 residue plays an important role in ligand binding [1].

1: A structural and functional investigation of a novel protein from Mycobacterium smegmatis implicated in mycobacterial macrophage survivability. Shahine A, Littler D, Brammananath R, Chan PY, Crellin PK, Coppel RL, Rossjohn J, Beddoe T; Acta Crystallogr D Biol Crystallogr. 2014;70:2264-2276. PMID:25195741