Calcium ATPase is a member of the P-type ATPases that transport ions across the membrane against a concentration gradient. Here we have solved the crystal structure of the calcium ATPase of skeletal muscle sarcoplasmic reticulum (SERCA1a) at 2.6 A resolution with two calcium ions bound in the transmembrane domain, which comprises ten alpha-helices. The two calcium ions are located side by side and are surrounded by four transmembrane helices, two of which are unwound for efficient coordination geometry. The cytoplasmic region consists of three well separated domains, with the phosphorylation site in the central catalytic domain and the adenosine-binding site on another domain. The phosphorylation domain has the same fold as haloacid dehalogenase. Comparison with a low-resolution electron density map of the enzyme in the absence of calcium and with biochemical data suggests that large domain movements take place during active transport.

http://www.iam.u-tokyo.ac.jp/StrBiol/resource/nature2000.pdf

Crystal structure of the calcium pump of sarcoplasmic reticulum at 2.6 Å resolution

Summary
The diets of over two-thirds of the world's population lack one or more essential mineral elements. This can be remedied through dietary diversification, mineral supplementation, food fortification, or increasing the concentrations and/or bioavailability of mineral elements in produce (biofortification). This article reviews aspects of soil science, plant physiology and genetics underpinning crop biofortification strategies, as well as agronomic and genetic approaches currently taken to biofortify food crops with the mineral elements most commonly lacking in human diets: iron (Fe), zinc (Zn), copper (Cu), calcium (Ca), magnesium (Mg), iodine (I) and selenium (Se). Two complementary approaches have been successfully adopted to increase the concentrations of bioavailable mineral elements in food crops. First, agronomic approaches optimizing the application of mineral fertilizers and/or improving the solubilization and mobilization of mineral elements in the soil have been implemented. Secondly, crops have been developed with: increased abilities to acquire mineral elements and accumulate them in edible tissues; increased concentrations of ‘promoter’ substances, such as ascorbate, β-carotene and cysteine-rich polypeptides which stimulate the absorption of essential mineral elements by the gut; and reduced concentrations of ‘antinutrients’, such as oxalate, polyphenolics or phytate, which interfere with their absorption. These approaches are addressing mineral malnutrition in humans globally.

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Biofortification of crops with seven mineral elements often lacking in human diets--iron, zinc, copper, calcium, magnesium, selenium and iodine.

Occurrence, classification, and biological function of hydrogenases: an overview.

Chemistry of biologically important synthetic organoselenium compounds.

▪ Abstract Iron-sulfur [Fe-S] clusters are ubiquitous and evolutionary ancient prosthetic groups that are required to sustain fundamental life processes. Owing to their remarkable structural plasticity and versatile chemical/electronic features [Fe-S] clusters participate in electron transfer, substrate binding/activation, iron/sulfur storage, regulation of gene expression, and enzyme activity. Formation of intracellular [Fe-S] clusters does not occur spontaneously but requires a complex biosynthetic machinery. Three different types of [Fe-S] cluster biosynthetic systems have been discovered, and all of them are mechanistically unified by the requirement for a cysteine desulfurase and the participation of an [Fe-S] cluster scaffolding protein. Important mechanistic questions related to [Fe-S] cluster biosynthesis involve the molecular details of how [Fe-S] clusters are assembled on scaffold proteins, how [Fe-S] clusters are transferred from scaffolds to target proteins, how various accessory proteins part...

Structure, function, and formation of biological iron-sulfur clusters

Cysteine desulfurase is a pyridoxal 5′-phosphate (PLP)-dependent homodimeric enzyme that catalyzes the conversion of L-cysteine to L-alanine and sulfane sulfur via the formation of a protein-bound cysteine persulfide intermediate on a conserved cysteine residue. Increased evidence for the functions of cysteine desulfurases has revealed their important roles in the biosyntheses of Fe-S clusters, thiamine, thionucleosides in tRNA, biotin, lipoic acid, molybdopterin, and NAD. The enzymes are also proposed to be involved in cellular iron homeostasis and in the biosynthesis of selenoproteins. The mechanisms for sulfur mobilization mediated by cysteine desulfurases are as yet unknown, but enzymes capable of providing a variety of biosynthetic pathways for sulfur/selenium-containing biomolecules are probably applicable to the production of cofactors and the bioconversion of useful compounds.

Bacterial cysteine desulfurases: their function and mechanisms

A psychrotrophic bacterium producing a cold-adapted lipase upon growth at low temperatures was isolated from Alaskan soil and identified as a Pseudomonas strain. The lipase gene (lipP) was cloned from the strain and sequenced. The amino acid sequence deduced from the nucleotide sequence of the gene (924 bp) corresponded to a protein of 308 amino acid residues with a molecular weight of 33,714. LipP also has consensus motifs conserved in other cold-adapted lipases, i.e., Lipase 2 from Antarctic Moraxella TA144 (G. Feller, M. Thiry, J. L. Arpigny, and C. Gerday, DNA Cell Biol. 10:381–388, 1991) and the mammalian hormone-sensitive lipase (D. Langin, H. Laurell, L. S. Holst, P. Belfrage, and C. Holm, Proc. Natl. Acad. Sci. USA 90:4897–4901, 1993): a pentapeptide, GDSAG, containing the putative active-site serine and an HG dipeptide. LipP was purified from an extract of recombinant Escherichia coli C600 cells harboring a plasmid coding for the lipP gene. The enzyme showed a 1,3-positional specificity toward triolein. p-Nitrophenyl esters of fatty acids with short to medium chains (C4 and C6) served as good substrates. The enzyme was stable between pH 6 and 9, and the optimal pH for the enzymatic hydrolysis of tributyrin was around 8. The activation energies for the hydrolysis of p-nitrophenyl butyrate and p-nitrophenyl laurate were determined to be 11.2 and 7.7 kcal/mol, respectively, in the temperature range 5 to 35°C. The enzyme was unstable at temperatures higher than 45°C. The Km of the enzyme for p-nitrophenyl butyrate increased with increases in the assay temperature. The enzyme was strongly inhibited by Zn2+, Cu2+, Fe3+, and Hg2+ but was not affected by phenylmethylsulfonyl fluoride and bis-nitrophenyl phosphate. Various water-miscible organic solvents, such as methanol and dimethyl sulfoxide, at concentrations of 0 to 30% (vol/vol) activated the enzyme.

A Cold-Adapted Lipase of an Alaskan Psychrotroph,Pseudomonas sp. Strain B11-1: Gene Cloning and Enzyme Purification and Characterization

We describe a simple method for enzymatic synthesis of L and D amino acids from alpha-keto acids with Escherichia coli cells which express heterologous genes L-amino acids were produced with thermostable L-amino acid dehydrogenase and formate dehydrogenase (FDH) from alpha-keto acids and ammonium formate with only an intracellular pool of NAD+ for the regeneration of NADH We constructed plasmids containing, in addition to the FDH gene, the genes for amino acid dehydrogenases, including ie, leucine dehydrogenase, alanine dehydrogenase, and phenylalanine dehydrogenase L-Leucine, L-valine, L-norvaline, L-methionine, L-phenylalanine, and L-tyrosine were synthesized with the recombinant E coli cells with high chemical yields (> 80%) and high optical yields (up to 100% enantiomeric excess) Stereospecific conversion of various alpha-keto acids to D amino acids was also examined with recombinant E coli cells containing a plasmid coding for the four heterologous genes of the thermostable enzymes D-amino acid aminotransferase, alanine racemase, L-alanine dehydrogenase, and FDH Optically pure D enantiomers of glutamate and leucine were obtained

Synthesis of optically active amino acids from alpha-keto acids with Escherichia coli cells expressing heterologous genes.

Cysteine sulfinate desulfinase, a nifs-like protein of escherichia coli with selenocysteine lyase and cysteine desulfurase activities : gene cloning, purification, and characterization of a novel pyridoxal enzyme

Nobuyoshi Esaki

Papers

Bacterial cysteine desulfurases: their function and mechanisms

A Cold-Adapted Lipase of an Alaskan Psychrotroph,Pseudomonas sp. Strain B11-1: Gene Cloning and Enzyme Purification and Characterization

Synthesis of optically active amino acids from alpha-keto acids with Escherichia coli cells expressing heterologous genes.

Cysteine sulfinate desulfinase, a nifs-like protein of escherichia coli with selenocysteine lyase and cysteine desulfurase activities : gene cloning, purification, and characterization of a novel pyridoxal enzyme

Crystal Structure of L-2-Haloacid Dehalogenase from Pseudomonas sp. YL: AN α/β HYDROLASE STRUCTURE THAT IS DIFFERENT FROM THE α/β HYDROLASE FOLD