Good thread, thanks all.
Here is paper showing that phosphorylation of a small basic membrane protein shifts pI from 10 to 6.7 (see isoelectric gel in Fig 4) http://www.ncbi.nlm.nih.gov/pubmed/3158660 Purification and characterization of phospholamban from canine cardiac sarcoplasmic reticulum. Jones LR, Simmerman HK, Wilson WW, Gurd FR, Wegener AD. J Biol Chem. 1985 Jun 25;260(12):7721-30. Following phosphorylation of phospholamban at Ser-16 by PKA, phosphorylation of phospholamban by CaMKII at a second site Thr-17 further shifts the pI to 5.7 For comparison, an online pI calculator predicts the following changes upon phospholamban phosphorylation pI number of phosphorylated residues 9.15 0 7.94 1 6.83 2 5.58 3 http://www.phosphosite.org/proteinAction.do?id=2713&showAllSites=true PLB sequence MDKVQYLTRS AIRRASTIEM PQQARQNLQN LFINFCLILI CLLLICIIVM LL -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of DK Sent: Wednesday, June 27, 2012 12:32 AM To: [email protected] Subject: Re: pI shift be Phosphorylation? In article <[email protected]>, Gerchman <[email protected]> wrote: > > >Greetings netters > >Does any one know how much shift in pI will be >expected by one phosphate addition? Two phosphate addition? etc? Depends on a protein! In theory, spans the range from "hardly anything" to "huge". For the crudest estimate, calculate pI of your protein with Protparam then for each phosphate change two serines to aspartates and calculate again. DK _______________________________________________ Methods mailing list [email protected] http://www.bio.net/biomail/listinfo/methods _______________________________________________ Methods mailing list [email protected] http://www.bio.net/biomail/listinfo/methods
