MALDI-TOF is suitable to identify whether a protein is a dimer or a trimer?

Leemor Joshua-Tor leemor at CSHL.ORG
Fri Jan 24 09:24:44 EST 1997

>MALDI-TOF analysis is suitable to identifying whether a protein is a
>homodimer or a homotrimer?
>I have a small DNA-binding protein(6,100 dalton) quite well purified.
>Through size exclusion HPLC gel chromatography, I found its effective
>molecular weight of the protein in the absence of its binding DNA
>sequence is about 19,000 dalton, close to homotrimer.
>But I am not sure that it is a trimer based on only the result becuase I
>didn't ever hear about homotrimer DNA binding protein; so I need some
>additional experiments confirming this fact.
>Thank you for your time and expertise,
>Lee, Ji Hyun

The best, most accurate, way to determine the molecular weight of your
sample and thus it's oligomeric form is by analytical ultracentrifugation.
Another example of a trimeric DNA-binding protein is the heat shock
transcription factor.


  Leemor Joshua-Tor, Ph.D.
  Assistant Investigator
  Keck Structural Biology
  Cold Spring Harbor Laboratory           Tel. (516) 367 8821
  1 Bungtown Road                         Fax  (516) 367 8873
  Cold Spring Harbor, NY 11724            e-mail: leemor at

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