Functional redundancy of transcription factor-binding sites in the killer cell Ig-like receptor (KIR) gene promoter.

Variegated expression of inhibitory killer cell Ig-like receptors (KIRs) for MHC class I molecules helps NK cells distinguish normal from aberrant self and avoid autoreactivity. Prior studies of KIR promoters have produced conflicting results and no cis-acting sites have been independently confirmed. We took a comprehensive linker-scanning mutagenesis approach and substituted 24 consecutive 10-bp segments in the human KIR3DL1 promoter.

Catalytic and structural effects of amino acid substitution at histidine 30 in human manganese superoxide dismutase: insertion of valine C gamma into the substrate access channel.

Catalysis of the disproportionation of superoxide by human manganese superoxide dismutase (MnSOD) is characterized by an initial burst of catalysis followed by a much slower region that is zero order in superoxide and due to a product inhibition by peroxide anion. We have prepared site-specific mutants with replacements at His30, the side chain of which lies along the substrate access channel and is about 5.8 A from the metal.

Partial reconstitution of human DNA mismatch repair in vitro: characterization of the role of human replication protein A.

DNA mismatch repair (MMR) is a critical genome-stabilization system. However, the molecular mechanism of MMR in human cells remains obscure because many of the components have not yet been identified. Using a functional in vitro reconstitution system, this study identified three HeLa cell fractions essential for in vitro MMR.