Beta-galactosidase

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*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]
*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]
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**This paper uses [http://probes.invitrogen.com/media/pis/mp02904.pdf C<sub>12</sub>FDG] from Invitrogen
==Reference==
==Reference==

Revision as of 16:26, 17 September 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
    • This paper uses C12FDG from Invitrogen

Reference

  1. isbn:3-11-014830-7. [Muller-Hill-1996]
  2. isbn:0317118099. [Beckwith-1970]
  3. Ullmann A. . pmid:1345751. PubMed HubMed [Ullmann-Bioessays-1992]
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