Rare arg codon causing expression problems?

[Chen Ho An]

The effect of the rare codons AGA/AGG is well documented and here's a
couple of review papers

Kurland & Gallant, Current Opinion in Biotechnology 1996 (7) 489-493
Kane, Current Opinion in Biotechnology 1995 (6) 494-500

See also 

Day et al, Protein Expression and Purification 8 1-16

for effect of AGA codon on quality of proteins produced.  There are many
papers published on this subject, just do a literature search or email me
if you are interested.

However the effect of these rare codons is not always straightforward.  I
found that having AGA as the second codon (after the start codon) 
expressed better than the more common one CGT, the reason is probably due
to the effect of secondary mRNA structure on the translation initiation.
There are also other reasons for the poor expression of protein which is
independent of the codon usage - I have changed the rare codons by
mutagenesis, some showed improvement in expression, but some don't.



-chen


_________________________________________________________________________

HA Chen				tel: 0171 391 1354
Department of Biochemistry	chen at biochem.ucl.ac.uk
University College London	http://www.biochem.ucl.ac.uk/~chen/
Gower Street
London WC1E 6BT
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