Dual recognition-incision enzymes might be involved in mismatch repair and meiosis.
Mismatch repair in many organisms depends on three proteins: the mismatch-recognition protein MutS, a nicking endonuclease MutH, and MutL, which acts as a scaffold between these. However, many genomes lack MutL but possess MutS. In one of these cases, in a coral mitochondrial genome, a gene is present that encodes a MutS protein fused to an HNH nicking endonuclease, potentially eliminating the requirement for MutL. Likewise, many prokaryotes could operate similarly, independently of MutL by encoding a fused MutS-Smr (MutS2) protein. Smr, which is proposed to be a nicking endonuclease, can also be found separately in many eukaryotes, where it might play a role in mismatch repair or meiotic chromosome crossing-over.
Malik
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Howard Hughes Medical Institute, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA.
Henikoff
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D000251:Adenosine Triphosphatases; D000595:Amino Acid Sequence; D000818:Animals; D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism / Q000502:physiology; D020137:Base Pair Mismatch; D003063:Cnidaria / Q000235:genetics / Q000378:metabolism; D004247:DNA / Q000096:biosynthesis; D004260:DNA Repair; D004268:DNA-Binding Proteins; D029968:Escherichia coli Proteins; D008928:Mitochondria / Q000378:metabolism; D008957:Models, Genetic; D008969:Molecular Sequence Data; D000070956:MutL Proteins; D051719:MutS DNA Mismatch-Binding Protein; D010802:Phylogeny; D017434:Protein Structure, Tertiary; D017386:Sequence Homology, Amino Acid
D001426:Bacterial Proteins; D004268:DNA-Binding Proteins; D029968:Escherichia coli Proteins; C074770:MutL protein, E coli; D004247:DNA; D000251:Adenosine Triphosphatases; D000070956:MutL Proteins; D051719:MutS DNA Mismatch-Binding Protein; C497175:MutS protein, E coli