Yeast Sequencing Report Cloning and sequencing the genomic encoding region of copper–zinc superoxide dismutase enzyme from several marine strains of the genus Debaryomyces (Lodder & Kreger-van Rij) Norma Y. Herna ´ndez-Saavedra* and Reyna Romero-Geraldo Centre for Biological Research of the Northwest (CIBNOR), Laboratory of Molecular Genetics, Marine Pathology Unit, PO Box 128, La Paz 23000, Baja California Sur, Me ´xico * Correspondence to: N. Y. Herna ´ndez-Saavedra, Centre for Biological Research of the Northwest (CIBNOR), Laboratory of Molecular Genetics, Marine Pathology Unit, PO Box 128, La Paz 23000, Baja California Sur, Me ´xico. E-mail: nhernan@cibnor.mx Received: 2 February 2001 Accepted: 3 May 2001 Abstract Copper–zinc superoxide dismutase (SODC) is a cytosolic enzyme which catalyses the dismutation of the superoxide radical. Due to its physiological importance, the encoding genes have been cloned from several species of higher eukaryotes. However, genes from moulds and yeast have not been studied extensively. In this paper, the encoding region of this gene (sod1) has been cloned from several strains of marine yeast belonging to the genus Debaryomyces (dvv sod1, dvy sod1 and dh sod1-61) through genomic DNA–PCR amplification. Fragments of 480–486 nucleotides were obtained, which contain information for products of 153–156 amino acids with calculated molecular masses of 15.8–16.6 kDa. The deduced amino acid sequence shows that D. vanrijiae enzymes present three additional amino acids not closely related to the active site conformation. In addition, in D. vanrijiae var. vanrijiae (strain 020), one histidine residue is apparently replaced by a proline; the incidence and function of other aromatic or heterocyclic amino acids is discussed. Homology and phylogenetic trees were constructed from amino-acid sequence multi- alignment analyses; the interrelationships among fungi are discussed. The sod-1 sequences reported in this paper were deposited in the public data library of the NCBI under Accession Nos AF301019, AF327449 and AF327448. Copyright # 2001 John Wiley & Sons, Ltd. Keywords: marine yeast; superoxide dismutase; SODC; Debaryomyces; cloning Introduction The superoxide dismutase enzyme (SOD EC 1.15.1.1) consists of a family of metalloproteins which catalyse the dismutation of the superoxide radical to form hydrogen peroxide through the reaction: 2eO x 2 +2H + pH 2 O 2 +O 2 (McCord and Fridovich, 1969). As a result of the prosthetic group linked to the active site, there are several isoforms of the enzyme, with CuZnSOD, MnSOD and FeSOD being the most commonly cited forms (Halliwell and Gutteridge, 1999). However, during the last 4 years uncommon and hybrid forms of the SOD family have been described: NiSOD, in organisms belonging to the genus Streptomyces (Youn et al., 1996a, b); FeMnSOD, widely described in organisms of the genus Streptococcus (Poyart, 1998); and finally, FeZnSOD, found in the genera Streptococcus and Streptomyces (Kim et al., 1998; Poyart et al., 1995). Because of its physiological importance in the cell, the CuZnSOD is found in a wide range of organisms (from viruses and bacteria to mammals), in contrast to the earlier view that this enzyme was restricted to the cytosol of eukaryotic cells. Each day a new record is added; as of April 2001 there were 132 entries corresponding to this enzyme in available databanks; 112 in SwissProt and 20 in TrEMBL (http://www.expasy.ch/sprot/sprot-top.html). Twenty of these reported sequences for CuZnSOD belong to non-eukaryotic organisms. The gene encoding SODC has been cloned from Yeast Yeast 2001; 18: 1227–1238. DOI: 10.1002 / yea.768 Copyright # 2001 John Wiley & Sons, Ltd.