Sandbox 666: Difference between revisions
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== Structure == | == Structure == | ||
EcoRI is a homodimer, so it has two identical subunits (<scene name='Sandbox_666/Monomer/3'>the constitutive monomer is shown here</scene>) of 31 kDa, but it possible to have homotetramers at high concentrations.. The constitutive monomers are 276 amino acids long. EcoRI and all the other restriction enzymes show a common structural core which is a α/β domain. The constitutive subunits of EcoRI are organized into a single α/β domain (five stranded β sheet which are surrounded on by α helices). Four β strands are parallel whereas the fourth is in an anti-parallel orientation to the others. | EcoRI is a homodimer, so it has two identical subunits (<scene name='Sandbox_666/Monomer/3'>the constitutive monomer is shown here</scene>) of 31 kDa, but it possible to have homotetramers at high concentrations.. The constitutive monomers are 276 amino acids long. EcoRI and all the other restriction enzymes show a common structural core which is a α/β domain. The constitutive subunits of EcoRI are organized into a single α/β domain (five stranded β sheet which are surrounded on by α helices). Four of these five β strands are parallel whereas the fourth (β4) is in an anti-parallel orientation to the others. | ||
The N-terminal section of each subunit forms, with a β-hairpin, an “arm” which wraps around the DNA molecule. (The arm brings the DNA molecule to the catalytic cleft.) | The N-terminal section of each subunit forms, with a β-hairpin, an “arm” which wraps around the DNA molecule. (The arm brings the DNA molecule to the catalytic cleft.) | ||
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The reaction is due to a catalytic sequence motif which is found in most type II restriction endonucleases: the PD…D/EXK motif. For EcoRI, this catalytic sequence is PD91 …E111AK. This motif is also responsible for Mg2+ binding(Asp90 and Glu111). | The reaction is due to a catalytic sequence motif which is found in most type II restriction endonucleases: the PD…D/EXK motif. For EcoRI, this catalytic sequence is PD91 …E111AK. This motif is also responsible for Mg2+ binding(Asp90 and Glu111). | ||
== References == | |||
== Application of EcoRI in molecular biology == | == Application of EcoRI in molecular biology == | ||
