Sandbox Reserved 967: Difference between revisions

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== Biological role ==

Ribonucleases H are the only known enzymes, able to degrade the RNA strand of a DNA/RNA hybrid in a sequence-nonspecific way.

There are two types of RNase H (RNases H1 and RNases H2) classified according to their sequence conservation and substrate preference. Currently, three types of RNA/DNA hybrids are known: simple RNA/DNA duplexes ('''Figure 1A'''), RNA•DNA/DNA hybrids ('''Figure 1B'''), and DNA•RNAfew•DNA/DNA hybrids ('''Figure 1C'''). RNases H2 is totally able to cleave a single ribonucleotide embedded in a double strand DNA (DNA• RNAfew •DNA/DNA type) when RNases H1 require at least 4 ribonucleotides. This ability and their high expression in proliferating cells suggest that RNases H2 are involved in DNA repair and replication.

There are two types of RNase H (RNases H1 and RNases H2) classified according to their sequence conservation and substrate preference. Currently, three types of RNA/DNA hybrids are known: simple RNA/DNA duplexes ('''Figure 1A'''), RNA•DNA/DNA hybrids ('''Figure 1B'''), and DNA•RNAfew•DNA/DNA hybrids ('''Figure 1C'''). RNases H2 is totally able to cleave a single ribonucleotide embedded in a double strand DNA (DNA• RNAfew •DNA/DNA type) when RNases H1 require at least 4 ribonucleotides. This ability and their high expression in proliferating cells suggest that RNases H2 are involved in DNA repair and replication<ref> Rychlik, Monika P., Hyongi Chon, Susana M. Cerritelli, Paulina Klimek, Robert J. Crouch, and Marcin Nowotny. “Crystal Structures of RNase H2 in Complex with Nucleic Acid Reveal the Mechanism of RNA-DNA Junction Recognition and Cleavage.” Molecular Cell 40, no. 4 (November 24, 2010): 658–70. doi:10.1016/j.molcel.2010.11.001.</ref>.

[[Image:ThreetypesofRNA-DNAhybrids.png|300px|left|thumb| '''Figure 1''' : Three types of RNA/DNA hybrids]]

Sandbox Reserved 967: Difference between revisions

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 == Biological role ==
 Ribonucleases H are the only known enzymes, able to degrade the RNA strand of a DNA/RNA hybrid in a sequence-nonspecific way.
-There are two types of RNase H (RNases H1 and RNases H2) classified according to their sequence conservation and substrate preference. Currently, three types of RNA/DNA hybrids are known: simple RNA/DNA duplexes ('''Figure 1A'''), RNA•DNA/DNA hybrids ('''Figure 1B'''), and DNA•RNAfew•DNA/DNA hybrids ('''Figure 1C'''). RNases H2 is totally able to cleave a single ribonucleotide embedded in a double strand DNA (DNA• RNAfew •DNA/DNA type) when RNases H1 require at least 4 ribonucleotides. This ability and their high expression in proliferating cells suggest that RNases H2 are involved in DNA repair and replication.
+There are two types of RNase H (RNases H1 and RNases H2) classified according to their sequence conservation and substrate preference. Currently, three types of RNA/DNA hybrids are known: simple RNA/DNA duplexes ('''Figure 1A'''), RNA•DNA/DNA hybrids ('''Figure 1B'''), and DNA•RNAfew•DNA/DNA hybrids ('''Figure 1C'''). RNases H2 is totally able to cleave a single ribonucleotide embedded in a double strand DNA (DNA• RNAfew •DNA/DNA type) when RNases H1 require at least 4 ribonucleotides. This ability and their high expression in proliferating cells suggest that RNases H2 are involved in DNA repair and replication<ref> Rychlik, Monika P., Hyongi Chon, Susana M. Cerritelli, Paulina Klimek, Robert J. Crouch, and Marcin Nowotny. “Crystal Structures of RNase H2 in Complex with Nucleic Acid Reveal the Mechanism of RNA-DNA Junction Recognition and Cleavage.” Molecular Cell 40, no. 4 (November 24, 2010): 658–70. doi:10.1016/j.molcel.2010.11.001.</ref>.
 [[Image:ThreetypesofRNA-DNAhybrids.png|300px|left|thumb| '''Figure 1''' : Three types of RNA/DNA hybrids]]