Cloning and primary structure of putative cytosolic and mitochondrial malate dehydrogenase from the mollusc Nucella lapillus (L.)

The evolutionary history of the malate dehydrogenase (MDH) gene family [NAD -dependent MDH; EC 1.1.1.37 and NAD(P)-dependent MDH; EC 1.1.1.82] has rece ived much attention. MDHs have also featured extensively as electrophoretic markers in population genetics and evolutionary ecology, and in many cases , intraspecific variation in MDH has been correlated with environmental var iables. However, while the amino acid residues essential for MDH function a re known, no studies have examined intraspecific nucleotide variation despi te evidence indicating that natural selection may be operating on this locu s. This study prevents two sets of degenerate oligonucleotide PCR primers t o facilitate the cloning of cytosolic MDH (cMDH) and mitochondrial MDH (mMD H) from a broad range of animals (cMDH) and animals and plants (mMDH). Thes e primers were used td obtain putative cMDH and mMDH cDNAs from the molluse Nucella lapillus. The N. lapillus cMDH cDNA was found to encode a putative cMDH protein of 334 aa and 36 kDa, while the mMDH cDNA encoded a putative mature mMDH protein of 315 aa and 33 kDa. The putative amino acid sequences of the two compartmentalised N. lapillus MDHs are presented and compared t o other known MDH sequences. (C) 2000 Elsevier Science B.V. All rights rese rved.