X-ray structure of fumarylacetoacetate hydrolase family member Homo sapiens FLJ36880

Abstract

The human protein FLJ36880 belongs to the fumarylacetoacetate hydrolase family. The X-ray structure of FLJ36880 has been determined to 2.2 A resolution employing the semi-automated high-throughput structural genomics approach of the Protein Structure Factory. FLJ36880 adopts a mixed beta-sandwich roll fold and forms homodimers in crystals as well as in solution. One Mg2+ ion is bound to each subunit of the dimeric protein by coordination to three carboxylate oxygens and three water molecules. These metal binding sites are accessible from the same surface of the dimer, partly due to the disorder of the undecapeptide stretch D29 to L39. The overall structure and metal binding site of FLJ36880 bear clear similarities to the C-terminal domain of the bifunctional enzyme HpcE from Escherichia coli C, fumarylacetoacetate hydrolase from Mus musculus and to YcgM (Apc5008) from E. coli 1262. These similarities provide a framework for suggesting biochemical functions and evolutionary relationships of FLJ36880. It appears highly probable that the metal binding sites are involved in an enzymatic activity related to the catabolism of aromatic amino acids. Two point mutations in the active-site of FAH, responsible for the metabolic disease hereditary tyrosinemia type I (HTI) in humans, affect residues that are structurally conserved in FLJ36880 and located in the putative catalytic site.

Structural Insight into Substrate Binding and Catalysis of a Novel 2-Keto-3-deoxy-d-arabinonate Dehydratase Illustrates Common Mechanistic Features of the FAH Superfamily

“…These structures include two putative enzymes from Thermus thermophilus HB8 (1WZO and 2DFU) ‡, 16,17 the protein YcgM (1NR9) from E. coli ‡, 18 and both the human protein FLJ36880 (1SAW) 19 and the yeast protein YNQ8_YEAST (1NKQ) ‡. 20 One biochemically characterized member is the bifunctional decarboxylase/isomerase HpcE (1I7O, 1GTT, EC 4.1.1.68/5.3.3.10) from E. coli C, which is involved in two consecutive steps of the homoprotocatechuate meta-fission pathway of aromatic compounds such as 3-and 4-hydroxyphenylacetate that ultimately leads to pyruvate and succinate.…”

Alterations of the mitochondrial proteome caused by the absence of mitochondrial DNA: A proteomic view

“…Apart from these really putative proteins, we also detected more interesting changes. Among them, a rather poorly characterized protein, homolog even at the 3-D structure level to a bacterial protein involved in the late steps of tyrosine degradation [33], and with a strong probability of mitochondrial localization.…”

Identification of FAH Domain-containing Protein 1 (FAHD1) as Oxaloacetate Decarboxylase

“…Oxaloacetate decarboxylases from prokaryotic organisms are well studied and are either soluble and divalent cation-dependent (like Cg1458) or membrane-bound and dependent on sodium and biotin (20). Molecular modeling based on the established x-ray structure of FAHD1 (9) revealed that indeed the catalytic centers of FAHD1 and Cg1458 are very similar and support a common catalytic mechanism.…”

“…Based on the structure of the active site, a hydroxylase or decarboxylase function was proposed. Also, a common function shared with other so far uncharacterized FAH proteins, E. coli YcgM and Thermus thermophilus TTHA0809, was suggested due to structural similarities (9). FAHD2 shows moderate sequence homology with FAHD1, but no further data are available for this enzyme at the moment.…”

“…In a recent study (10), we utilized a bioinformatics approach to show for the first time that FAHD1 is closely related to the prokaryotic fumarylpyruvate hydrolase NagK (11). This finding was derived from the fact that charged residues present in the catalytic center of FAHD1 and likely involved in its enzymatic function (9) are fully conserved between NagK and FAHD1. Enzymatic assays performed with the purified protein confirmed that FAHD1 is able to hydrolyze substrates of the acylpyruvate class in vitro.…”