Superoxide dismutase crystal structures

Wuerges J, J-W Lee, Y-I Yim, H-S Yrm, S-O Kang, KD Carugo (2004) Crystal structure of nickel-containing superoxide dismutase reveals another type of active site. Proc Natl Acad Sci USA 101 8569-8574. 

Nickel is found in thiolate/sulflde environment in the [NiFe]-hydrogenases and in CODH/ACS.33 In addition, either a mononuclear Ni-thiolate site or a dinuclear cysteine-S bridged structure are assumed plausible for the new class of Ni-containing superoxide dismutases, NiSOD (A).34 [NiFe]-hydrogenase catalyzes the two-electron redox chemistry of dihydrogen. Several crystal structures of [NiFe]-hydrogenases have demonstrated that the active site of the enzyme consists of a heterodinuclear Ni—Fe unit bound to thiolate sulfurs of cysteine residues with a Ni—Fe distance below 3 A (4) 35-39 This heterodinuclear active site has been the target of extensive model studies, which are summarized in Section 6.3.4.12.5. 

One last class of mononuclear non-haem iron enzyme that we have not yet considered, consists of the microbial superoxide dismutases with Fe(III) at their active site. The crystal structure of the E. coli enzyme shows a coordination geometry reminiscent of protocatechuate 3,4-dioxygenase, with four endogenous protein ligands, three His and one Asp residue, and one bound water molecule (Carlioz et ah, 1988). 

A. Carlioz, M.L. Ludwig, W.C. Stallings, J.A. Fee, H.M. Steinman, and D. Touati, Iron superoxide dismutase. Nucleotide sequence of the gene from Escherichia coli K12 and correlations with crystal structures. J. Biol. Chem. 263, 1555-1562 (1988). 

Crystal structure determinations of MnSODs from organisms ranging from E. coli to humans have been reported. Structural determinations of note include those by Jameson et al. on the E. coli enzyme and mutant forms of this enzyme with atomic resolution,a cambialistic superoxide dismutase from Porphyromonas gingivalis, and mutant forms of the human enzyme the Q143N, and Q143A mutants.The coordination sphere of the... 

Quint P et al (2006) Crystal structure of nitrated human manganese superoxide dismutase mechanism of inactivation. Free Radio Biol Med 40 453-458 PDBID 2ADQ... 

Mn catalase cycles between the Mn /Mfo and the Mn /Mn oxidation states during catalysis and is thus, in some sense, the two-electron analog of Mn superoxide dismutase. One possible mechanistic model, based on the known coordination chemistry of Mn dimers and the crystal structures of Mn catalase, is shown in Scheme 3. In this scheme, the bridging solvent molecules play a critical role in... 

The nickel enzymes covered in this article can be divided into two groups redox enzymes and hydrolases. The five Ni redox enzymes are hydrogenase, CO dehydrogenase (CODH), acetyl-CoA synthase (ACS), methyl-Coenzyme M reductase (MCR), and superoxide dismutase (SOD). Glyoxalase-I and urease are Ni hydrolases. Ni proteins that are not enzymes are not covered, because they have been recently reviewed. These include regulatory proteins (NikR) and chaperonins and metal uptake proteins (CooJ, CooE, UreE, and ABC transporters). A recent crystal structure of NikR, shown in Figure l(i), is a notable recent achievement in this area. ... 

Superoxide dismutase catalyzes the disproportionation of superoxide as 2O2 -i- 2H — O2 -I- H2O2. The Cu,Zn-superoxide dismutases are widely distributed in both plant and animal kingdoms and are found in eukaryotic cytosols. The vast majority of studies on superoxide dismutases have been made on the enzyme from bovine erythrocytes this enzyme contains 151 amino acid residues and two copper and two zinc atoms per molecule of —32,000 Da. The crystal structure of this protein has been reported (97), and the active site was shown to consist of a bimetallic (Cu,Zn) assembly (see Fig. 6). A type-2 copper center is... 

It has been concluded from a study of the optical and e.p.r. spectra of Co —Cu bovine superoxide dismutase, in which zinc has been replaced by cobalt, that the cobalt site reactivity should be described in terms of reaction of the Co-imidazolate-Cu system as a whole the crystal structure reported last year indicated that the metals were linked by a common histidine residue. There is an exchange interaction between the cobalt and copper however, this is abolished when the linking imidazole is protonated. Further evidence for the close proximity and interactive dependence of the zinc and copper binding sites was obtained from a study of the 4 Cu protein a two-fold enhancement of the activity of 2 Cu dismutase was observed upon occupation of the zinc sites by the Cu ". On the basis of C1 n.m.r. studies, Fee and Ward have suggested that one co-ordination position of Cu in superoxide dismutase is normally occupied by water they further suggest that superoxide can displace the solvent to form a cupric peroxide complex. 

The crystal structure of the superoxide dismutase, noted Cu2Zn2SOD, has been solved107 l081. The protein contains two identical Cu(II)Zn(II) pairs per functioning unit. 

Guan Y, Hickey MJ, Borgstahl GE, Hallewell RA, Lepock JR, O Connor D, Hsieh Y, Nick HS, Silverman DN and Tainer JA (1998) Crystal structure of Y34F mutant human mitochondrial manganese superoxide dismutase and the functional role of tyrosine 34. Biochemistry 37 4722-4730. 

I. The Need for Superoxide Dismutase II. The Crystal Structures of Dimeric Copper-Zinc Superoxide Dismutases... 

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