The vpr gene of human immunodeficiency virus type 1 (HIV-1) is one of the seven accessory genes that are believed to have roles in the virus replication cycle. We report here the detection of a 13 kD vpr protein in sucrose gradient-purified HIV-1. This protein was not detected in cells infected with a virus having a truncated vpr gene that lacks the potential to encode for 26 C-terminal amino acid residues. These findings raise the possibility that virion-associated vpr proteins may be involved in the early life cycle of HIV-1 replication and suggest that the C-terminal region of the vpr gene is essential for its expression.

More than 20 consensus N-linked glycosylation sites occur in the gpl20 coding sequence of most isolates of human immunodeficiency virus type 1. Based on the N-linked glycosylation pattern of a well-characterized recombinant gpl20, it is likely that N-linked sugars are present at most, if not all, of the consensus glycosylation sites of the heavily glycosylated gpl20. In this study, we evaluated the relative importance of each of the 24 N-linked glycosylation sites of gpl20 in the molecular clone HXB2 to viral infectivity. The ability of HXB2-derived mutants, each having 1 of the 24 N-linked glycosylation sites mutated by site-directed mutagenesis, to infect CD4-positive SupTl cells was compared with that of the wild-type virus. We found that most of the individual consensus N-linked glycosylation sites are dispensable for viral infectivity. The five consensus N-linked glycosylation sites that are likely to have important roles in infectivity are all located in the amino-terminal half of gp120, indicating that the N-linked glycosylation sites that are important for infectivity of human immunodeficiency virus type 1 are not randomly distributed in gpl20. We predict that a partially glycosylated gp120 with most of the dispensable N-linked glycosylation sites removed may be a better vaccine candidate than the fully glycosylated gpl20.

Background: Biogenic emissions of methyl halides (CH 3 Cl, CH 3 Br and CH 3 I) are the major source of these compounds in the atmosphere; however, there are few reports about the halide profiles and strengths of these emissions. Halide ion methyltransferase (HMT) and halide/thiol methyltransferase (HTMT) enzymes concerning these emissions have been purified and characterized from several organisms including marine algae, fungi, and higher plants; however, the correlation between emission profiles of methyl halides and the enzymatic properties of HMT/ HTMT, and their role in vivo remains unclear.

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Phenylacetaldehyde reductase (PAR) produced by styreneassimilating Corynebacterium strain ST-10 was used to synthesize chiral alcohols. This enzyme with a broad substrate range reduced various prochiral aromatic ketones and b-ketoesters to yield optically active secondary alcohols with an enantiomeric purity of more than 98% enantiomeric excess (e.e.). The Escherichia coli recombinant cells which expressed the par gene could efficiently produce important pharmaceutical intermediates; (R)-2-chloro-1-(3-chlorophenyl)ethanol (28 mgAEmL )1 ) from m-chlorophenacyl chloride, ethyl (R)-4-chloro-3-hydroxy butanoate) (28 mgAEmL )1 ) from ethyl 4-chloro-3-oxobutanoate and (S)-N-tert-butoxycarbonyl(Boc)-3-pyrrolidinol from N-Boc-3-pyrrolidinone (51 mgAEmL )1 ), with more than 86% yields. The high yields were due to the fact that PAR could concomitantly reproduce NADH in the presence of 3-7% (v/v) 2-propanol in the reaction mixture. This biocatalytic process provided one of the best asymmetric reductions ever reported.