Slow base excision by human alkyladenine DNA glycosylase limits the rate of formation of AP sites and AP endonuclease 1 does not stimulate base excision.

The base excision repair pathway removes damaged DNA bases and resynthesizes DNA to replace the damage. Human alkyladenine DNA glycosylase (AAG) is one of several damage-specific DNA glycosylases that recognizes and excises damaged DNA bases. AAG removes primarily damaged adenine residues.

Changes in transcription within the CA1 field of the hippocampus are associated with age-related spatial learning impairments.

Aged rats display a broad range of behavioral performance in spatial learning. The aim of this study was to identify candidate genes that are associated with learning and memory impairments. We first categorized aged-superior learners and age learning-impaired rats based on their performance in the Morris water maze (MWM) and then isolated messenger RNA from the CA1 hippocampal region of each animal to interrogate Affymetrix microarrays.

The phosphoprotein (P) and L binding sites reside in the N-terminus of the L subunit of the measles virus RNA polymerase.

Measles virus encodes an RNA-dependent RNA polymerase composed of the L and P proteins. Recent studies have shown that the L proteins of both Sendai virus and parainfluenza virus 3 form an L-L complex [Cevik, B., Smallwood, S.

Contribution of a conserved phenylalanine residue to the activity of Escherichia coli uracil DNA glycosylase.

Uracil DNA glycosylase (UDG) excises uracil from DNA to initiate repair of this lesion. This important DNA repair enzyme is conserved in viruses, bacteria, and eukaryotes. One residue that is conserved among all the members of the UDG family is a phenylalanine that stacks with uracil when it is flipped out of the DNA helix into the enzyme active site.

Mapping the phosphoprotein binding site on Sendai virus NP protein assembled into nucleocapsids.

To catalyze RNA synthesis, the Sendai virus P-L RNA polymerase complex first binds the viral nucleocapsid (NC) template through an interaction of the P subunit with NP assembled with the genome RNA. For replication, the polymerase utilizes an NP(0)-P complex as the substrate for the encapsidation of newly synthesized RNA which involves both NP-RNA and NP-NP interactions. Previous studies showed that the C-terminal 124 amino acids of NP (aa 401-524) contain the P-NC binding site.

Effects of hydrogen bonding within a damaged base pair on the activity of wild type and DNA-intercalating mutants of human alkyladenine DNA glycosylase.

Human alkyladenine DNA glycosylase "flips" damaged DNA bases into its active site where excision occurs. Tyrosine 162 is inserted into the DNA helix in place of the damaged base and may assist in nucleotide flipping by "pushing" it. Mutating this DNA-intercalating Tyr to Ser reduces the DNA binding and base excision activities of alkyladenine DNA glycosylase to undetectable levels demonstrating that Tyr-162 is critical for both activities.

The C-terminal 88 amino acids of the Sendai virus P protein have multiple functions separable by mutation.

The Sendai virus P-L polymerase complex binds the NP-encapsidated nucleocapsid (NC) template through a P-NP interaction. To identify P amino acids responsible for binding we performed site-directed mutagenesis on the C-terminal 88 amino acids in the NC binding domain. The mutant P proteins expressed from plasmids were assayed for viral RNA synthesis and for various protein-protein interactions.