What is McrBC?

McrBC is an endonuclease which cleaves DNA containing methylcytosine* on one or both strands. Sites on the DNA recognized by McrBC consist of two half-sites of the form (G/A)mC. These half-sites can be separated by up to 3 kb, but the optimal separation is 55-103 base pairs.

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Why is McrBC an unusual restriction endonuclease?

The McrBC endonuclease is unique in several respects: it is the only endonuclease among the large and functionally divergent AAA+ family of proteins and it is the only restriction endonuclease with a ring-like structure.

What does restriction digestion do?

Restriction Digestion is the process of cutting DNA molecules into smaller pieces with special enzymes called Restriction Endonucleases (sometimes just called Restriction Enzymes or RE’s).

How do restriction enzymes cut DNA sequences?

When a restriction endonuclease recognizes a sequence, it snips through the DNA molecule by catalyzing the hydrolysis (splitting of a chemical bond by addition of a water molecule) of the bond between adjacent nucleotides.

How do you determine the size of restriction fragments?

First, work out the frequency of occurrence of the restriction site as 1-in-x bases, as explained in the example for the Intermediate level calculation. Then take the size of the DNA in kb (kilobases) and multiply by 1000 to get the size in bases. Divide this by x and round to the nearest whole number.

How do I find restriction sites on a sequence?

Jump to the location of the enzyme on the sequence Hover over the enzyme to see buffer information, and to jump to the cut site on the sequence. Click on an enzyme to select it. Notice that the cut site on the sequence map turns colored.

Are restriction enzymes palindromic sequence?

Restriction enzymes cut double-stranded DNA * at specific locations based the pattern of bases found at those locations. These enzymes predictably cut both strands because the sequences they recognize are palindromic.

Why do restriction enzymes recognize palindromic sequences?

A palindromic sequence is the same backwards and forwards on both sides (see image below). This means that the enzyme recognizes the sequence no matter from which side the enzyme approaches the DNA. A palindromic sequence also increases the chance that both strands of DNA are cut.

What is the difference between the McrB and MCRC genes?

The mcrB gene elaborates two protein products, only one of which is required for activity in vitro, but both of which contain a conserved amino acid sequence motif identified as a possible GTP-binding site. The mcrC gene product contains a leucine heptad repeat that could play a role in protein-protein interactions.

What is McrBC used for?

McrBC is a tool for determining the methylation state of CpG dinucleotides (6-10). McrBC will act upon a pair of Pu m CG sequence elements, thereby detecting a high proportion of methylated CpGs, but will not recognize HpaII/MspI sites (CCGG) in which the internal cytosine is methylated.

What are the sites on the DNA recognized by McrBC?

Sites on the DNA recognized by McrBC consist of two half-sites of the form (G/A)mC. These half-sites can be separated by up to 3 kb, but the optimal separation is 55-103 base pairs. McrBC is an endonuclease which cleaves DNA containing methylcytosine* on one or both strands. McrBC will not act upon unmethylated DNA (1).

How does McrBC cleave DNA?