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The nucleotide sequence of the abnx cDNA gene, which encodes an exo-arabinanase (Abnx) of Penicillium chrysogenum 31B, was determined. Abnx was found to be structurally distinct from known arabinan-degrading enzymes based on its amino acid sequence and a hydrophobic cluster analysis. The protein in the protein database with the highest similarity to Abnx was the Neurospora crassa conserved hypothetical protein. The abnx cDNA gene product expressed in Escherichia coli catalyzed the release of arabinobiose from α-1,5-L-arabinan. The activity of the recombinant Abnx towards a series of arabino-oligosaccharides, as expressed by kcat/Km value, was greatest with arabinohexaose. [Copyright &y& Elsevier]

The first animal polygalacturonase (PG, EC 2.1.15) encoding cDNA, Mi-pg-1, was cloned from the plant parasitic nematode Meloidogyne incognita. The enzymatic activity of MI-PG-1 was confirmed after heterologous expression in Escherichia coli. The presence of a predicted signal peptide on the MI-PG-1 sequence together with the specific localization of the transcripts of the Mi-pg-1 gene in the oesophageal glands of infective juveniles imply that MI-PG-1 could be secreted into plant tissues. The potential role of MI-PG-1 in parasitism is discussed. [Copyright &y& Elsevier]

We report identification and characterization of Kv6.3, a novel member of the voltage-gated K+ channel. Reverse transcriptase-polymerase chain reaction analysis indicated that Kv6.3 was highly expressed in the brain. Electrophysiological studies indicated that homomultimeric Kv6.3 did not yield a functional voltage-gated ion channel. When Kv6.3 and Kv2.1 were co-expressed, the heteromultimeric channels displayed the decreased rate of deactivation compared to the homomultimeric Kv2.1 channels. Immunoprecipitation studies indicated that Kv6.3 bound with Kv2.1 in co-transfected cells. These results indicate that Kv6.3 is a novel member of the voltage-gated K+ channel which functions as a modulatory subunit. [Copyright &y& Elsevier]