The RecA/Rad51 protein carries out strand exchange during homologous recombination. Indicate true (T) and false (F) statements about this process below. Your answer would be a four-letter string composed of letters T and F only, e.g. FFFF.
( ) RecA hydrolyzes ATP upon binding to the invading DNA strand.
( ) RecA forces the invading strand into a conformation that fully mimics the geometry of a long DNA double helix.
( ) Sampling of the homologous duplex by the invading strand is likely to occur in triplet nucleotide blocks.
( ) RecA-bound, invading, single-stranded DNA binds and destabilizes the homologous duplex to allow the sampling of its sequence by base-pairing.

Question

The RecA/Rad51 protein carries out strand exchange during homologous recombination. Indicate true (T) and false (F) statements about this process below. Your answer would be a four-letter string composed of letters T and F only, e.g. FFFF.
( )	RecA hydrolyzes ATP upon binding to the invading DNA strand.
( )	RecA forces the invading strand into a conformation that fully mimics the geometry of a long DNA double helix.
( )	Sampling of the homologous duplex by the invading strand is likely to occur in triplet nucleotide blocks.
( )	RecA-bound, invading, single-stranded DNA binds and destabilizes the homologous duplex to allow the sampling of its sequence by base-pairing.

Quizplus · Accepted Answer

RecA binds cooperatively to the invading strand, forcing blocks of three nucleotides into a conformation mimicking that of three nucleotides in a double helix (although, between adjacent triplets, the DNA backbone is untwisted and stretched out). This complex then binds and destabilizes the target homologous duplex, allowing the sampling to take place by base-pairing interactions. RecA hydrolyzes its bound ATP after the strand exchange is completed.

The RecA/Rad51 Protein Carries Out Strand Exchange During Homologous Recombination