Crystal structure of hypothetical protein YfiH from Shigella flexneri at 2 Å resolution

Abstract

The crystal structure of an uncharacterized conserved protein (residues 1–243) expressed by yfiH gene of Shigella flexneri 2a str.2457T (gi 30042248),1 has been determined and refined to 2.01 A by single wavelength anomalous dispersion (SAD) method. The YfiH protein belongs to a vast protein family of at least 201 uncharacterized proteins which contain conservative Pfam motif PF02578 (DUF152) (residues 29 –243) and TIGR motif (TIGR00726)2,3 (residues 25–243). The YfiH protein belongs to the COG1496 which consists of 39 proteins widely distributed in 37 species from bacteria to human. The yfiH gene (DNA bases 101,672-102,403)1 is located between the two genes, clpB and sfhB. The clpB gene is thought to encode an adenosine triphosphatase subunit of an intracellular adenosine 5′-triphosphate-dependent protease which belongs to the ClpA/ClpB family and is induced by heat shock.4 The sfhB gene expresses a protein which is known as suppressor of ftsH mutation and is responsible for synthesis of pseudouridine from uracil at three positions in 23S ribosomal RNA.5 The function of YfiH protein is unknown, but preliminary data obtained for Brevibacterium lactofermentum ATCC 13869 show that the gene is not essential for the cell’s growth and viability.6