Beta-galactosidase: Difference between revisions
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*A mutant with an internal deletion of codons 21-41 of the lacZ gene does not produce any active β-galactosidase. | *A mutant with an internal deletion of codons 21-41 of the lacZ gene does not produce any active β-galactosidase. | ||
*A mutant with a deletion of everything past residue 60 (i.e. it expresses only the first 60 N-terminal amino acids) does not produce any active β-galactosidase. | *A mutant with a deletion of everything past residue 60 (i.e. it expresses only the first 60 N-terminal amino acids) does not produce any active β-galactosidase. | ||
*You can measure lacZ activity using flow cytometry. See [http://www.cyto.purdue.edu/flowcyt/research/micrflow/jepras/jepras2.htm A flow cytometric study of stationary phase gene expression in E.coli using lacZ reporter gene fusion] | |||
==Reference== | ==Reference== | ||
Revision as of 05:53, 23 August 2007
Some interesting facts [1]
- A tetramer of 4 identical subunits
- Each subunit is 120kD.
- Active only as a tetramer.
- Mutations in some of the codons of the N-terminal 60aa or C-terminal 100aa results in an inactive, dimeric β-galactosidase. [2]
- If the above sequences are deleted, the missing protein fragment can be replaced by the corresponding peptide. This is called intracistronic alpha or omega complementation respectively.
- Its N-terminal 23 residues can be replaced by any amino acid residues without affecting the enzymatic activity.
- A mutant with an internal deletion of codons 21-41 of the lacZ gene does not produce any active β-galactosidase.
- A mutant with a deletion of everything past residue 60 (i.e. it expresses only the first 60 N-terminal amino acids) does not produce any active β-galactosidase.
- You can measure lacZ activity using flow cytometry. See A flow cytometric study of stationary phase gene expression in E.coli using lacZ reporter gene fusion
