Runswick MJ et al. (1994) DNA Seq "Extension of the mitochondrial transporter super-family: sequences of five members from the nematode worm, Caenorhabditis elegans."

Phillipi A, Runswick MJ, Walker JE, Lauria G

[DNA Seq, 1994]

The sequences are presented of cDNAs encoding five related proteins from the nematode worm, Caenorhabditis elegans. Three of them can be recognised as the homologues of the ADP/ATP, phosphate and oxoglutarate/malate carrier proteins that have been found in the inner membranes of mitochondria in other species. These carrier proteins, and the uncoupling protein from the mitochondria in mammalian brown adipose tissue, have common features in their primary and secondary structures, and are members of the same protein super-family. Members of this super-family have polypeptide chains approximately 300 amino acid long that consist of three tandem related sequences of about 100 amino acids. The tandem repeats from the different proteins are inter-related, and each repeat is probably folded into a common secondary structural motif consisting of two hydrophobic stretches of amino acids with the potential to form membrane spanning alpha-helices, linked by an extensive hydrophilic region. The common characteristic features of this family of proteins are also present in sequences of two further proteins, named C1 and C2, encoded in nematode cDNAs, and in tour published protein sequences from various sources. Neither the transport properties nor the subcellular locations of any of this latter group of six proteins are known. Therefore, currently the super-family of mitochondrial carrier proteins has at least ten different members.

Bichai F et al. (2009) Water Res "Protection against UV disinfection of E. coli bacteria and B. subtilis spores ingested by C. elegans nematodes."

Barbeau B, Bichai F, Payment P

[Water Res, 2009]

Nematodes, which occur abundantly in granular media filters of drinking water treatment plants and in distribution systems, can ingest and transport pathogenic bacteria and provide them protection against chemical disinfectants. However, protection against UV disinfection had not been investigated to date. In this study, Caenorhabditis elegans nematodes (wild-type strain N2) were allowed to feed on Escherichia coli OP50 and Bacillus subtilis spores before being exposed to 5 and 40 mJ/cm(2) UV fluences, using a collimated beam apparatus (LP, 254 nm). Sonication (15 W, 60s) was used to extract bacteria from nematode guts following UV exposure in order to assess the amount of ingested bacteria that resisted the UV treatment using a standard culture method. Bacteria located inside the gut of C. elegans were shown to benefit from a significant protection against UV. Approximately 15% of the applied UV fluence of 40 mJ/cm(2) (as typically used in WTP) was found to reach the bacteria located inside nematode guts based on the inactivation of recovered bacteria (2.7 log reduction of E. coli bacteria and 0.7 log reduction of B. subtilis spores at 40 mJ/cm(2)). To our knowledge, this study is the first demonstration of the protection effect of bacterial internalization by higher organisms against UV treatment, using the specific case of E. coli and B. subtilis spores ingested by C. elegans.

Fiermonte G et al. (1998) J Biol Chem "The sequence, bacterial expression, and functional reconstitution of the rat mitochondrial dicarboxylate transporter cloned via distant homologs in yeast and Caenorhabditis elegans."

Lasorsa FM, Palmieri F, Walker JE, Runswick MJ, Palmieri L, Dolce V, Fiermonte G

[J Biol Chem, 1998]

The dicarboxylate carrier (DIC) belongs to a family of transport proteins found in the inner mitochondrial membranes. The biochemical properties of the mammalian protein have been characterized, but the protein is not abundant. It is difficult to purify and had not been sequenced. We have used the sequence of the distantly related yeast DIC to identify a related protein encoded in the genome of Caenorhabditis elegans. Then, related murine expressed sequence tags were identified with the worm sequence, and the murine sequence was used to isolate the cDNA for the rat homolog. The sequences of the worm and rat proteins have features characteristic of the family of mitochondrial transport proteins. Both proteins were expressed in bacteria and reconstituted into phospholipid vesicles where their transport characteristics closely resembled those of whole rat mitochondria and of the rat DIC reconstituted into vesicles. As expected from the role of the DIC in gluconeogenesis and ureogenesis, its transcripts were detected in rat liver and kidney, but unexpectedly, they were also detected in rat heart and brain tissues where the protein may fulfill other roles, possibly in supplying substrates to the Krebs cycle.

Walker JE et al. (1992) J Mol Biol "Sequences of 20 subunits of NADH:ubiquinone oxidoreductase from bovine heart mitochondria. Application of a novel strategy for sequencing proteins using the polymerase chain reaction."

Fearnley IM, Pilkington SJ, Medd SM, Arizmendi JM, Finel M, Runswick MJ, Dupuis A, Skehel JM, Walker JE

[J Mol Biol, 1992]

NADH:ubiquinone oxidoreductase, the first enzyme in the respiratory electron transport chain of mitochondria, is a membrane-bound multi-subunit assembly, and the bovine heart enzyme is now known to contain about 40 different polypeptides. Seven of them are encoded in the mitochondrial DNA; the remainder are the products of nuclear genes and are imported into the organelle. The primary structures of 12 of the nuclear coded subunits have been described and those of a further 20 are described here. The subunits have been sequenced by following a strategy based on the polymerase chain reaction. This strategy has been tailored from existing methods with the twofold aim of avoiding the use of cDNA libraries, and of obtaining a cDNA sequence rapidly with minimal knowledge of protein sequence, such as can be determined in a single N-terminal sequence experiment on a polypeptide spot on a two-dimensional gel. The utility and speed of this strategy have been demonstrated by sequencing cDNAs encoding 32 nuclear-coded-membrane associated proteins found in bovine heart mitochondria, and the procedures employed are illustrated with reference to the cDNA sequence of the 20 subunits of NADH:ubiquinone oxidoreductase that are presented. Extensive use has also been made of electrospray mass spectrometry to measure molecular masses of the purified subunits. This has corroborated the protein sequences of subunits with unmodified N terminals, and their measured molecular masses agree closely with those calculated from the protein sequences. Nine of the subunits, B8, B9, B12, B13, B14, B15, B17, B18 and B22 have modified alpha-amino groups. The measured molecular masses of subunits B8, B13, B14 and B17 are consistent with the post-translational removal of the initiator methionine and N-acetylation of the adjacent amino acid. The initiator methionine of subunit B18 has been removed and the N-terminal glycine modified by myristoylation. Subunits B9 and B12 appear to have N-terminal and other modifications of a hitherto unknown nature. The sequences of the subunits of bovine complex I provide important clues about the location of iron-sulphur clusters and substrate and cofactor binding sites, and give valuable information about the topology of the complex. No function has been ascribed to many of the subunits, but some of the sequences indicate the presence of hitherto unsuspected biochemical functions. Most notably the identification of an acyl carrier protein in both the bovine and Neurospora crassa complexes provides evidence that part of the complex may play a role in fatty acid biosynthesis in the organelle, possibly in the formation of cardiolipin.(ABSTRACT TRUNCATED AT 400 WORDS)