Site-Directed Mutagenesis

Rafael Maldonado rafael at howard.genetics.utah.edu
Mon Mar 17 14:05:17 EST 1997


On Fri, 14 Mar 1997, Rani Geha wrote:
> My question is: Is there a preference as to which codon to chose 
> for a particular amino acid change, or can I chose any of the 
> codons that code for an amino acid?

You should choose codons used at the same rate than the one you are 
replacing, or very common codons so your protein is not affected with 
some rare codon. You will need a codon usage table for yeast. There are 
many around, and since the genome is completed already, probably they have 
got absolute numbers. Check: 

http://www.dna.affrc.go.jp/~nakamura/CUTG.html

> I am also constructing a C-terminally truncated form of the gene 
> by introding a stop codon near the C-terminus. Again, is there a 
> preference as to which stop codon to use, i.e. TAA, TAG, or TGA?

There are also preference for termination codons, and it looks like some 
are more effective than others. In yeast, the favorite codon is UAAG. 
Yes, it is a four bases codon, but in termination codons the fouth base 
is very important also. Check:

Brown et al (1990), NAR 18, 6339


Rafa



___________________________________________________________________
                                             |
Rafael Maldonado                             | 'No te creas todo 
room 6160 Eccles Institute of Human Genetics |  lo que leas en
Department of Human Genetics		     |  internet.'
University of Utah			     |
Salt Lake City, Utah 84112. USA.	     |  "Don't believe  
Rafael.Maldonado at genetics.utah.edu           |  everything you read
Rafael at howard.genetics.utah.edu	             |  in internet."
Tel: 801-581-4429			     |
Fax: 801-585-3910			     |	
					                  






More information about the Methods mailing list