Beta-galactosidase: Difference between revisions
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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] | ||
**This paper uses [http://probes.invitrogen.com/media/pis/mp02904.pdf C<sub>12</sub>FDG] from Invitrogen | **This paper uses [http://probes.invitrogen.com/media/pis/mp02904.pdf C<sub>12</sub>FDG] from Invitrogen. However, FDG might be a better substrate in gram-negative bacteria like ''Escherichia coli'' <cite>Plovins-ApplEnvironMicrobio-1994</cite> | ||
==Reference== | ==Reference== | ||
| Line 17: | Line 17: | ||
#Beckwith-1970 isbn=0317118099 | #Beckwith-1970 isbn=0317118099 | ||
#Ullmann-Bioessays-1992 pmid=1345751 | #Ullmann-Bioessays-1992 pmid=1345751 | ||
#Plovins-ApplEnvironMicrobio-1994 pmid=7811104 | |||
</biblio> | </biblio> | ||
[[Category:Material]] [[Category:Enzyme]] [[Category:Reporter]] | [[Category:Material]] [[Category:Enzyme]] [[Category:Reporter]] | ||
Revision as of 15:03, 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
Reference
- ISBN:3-11-014830-7
- ISBN:0317118099
- Plovins A, Alvarez AM, Ibañez M, Molina M, and Nombela C. Use of fluorescein-di-beta-D-galactopyranoside (FDG) and C12-FDG as substrates for beta-galactosidase detection by flow cytometry in animal, bacterial, and yeast cells. Appl Environ Microbiol. 1994 Dec;60(12):4638-41. DOI:10.1128/aem.60.12.4638-4641.1994 |
- Ullmann A. Complementation in beta-galactosidase: from protein structure to genetic engineering. Bioessays. 1992 Mar;14(3):201-5. DOI:10.1002/bies.950140311 |
