Peanut lectin, when we solved the structure in the 90's, had a very unusual non-symmetric tetramer. Till we solved the structure, there were examples only of symmetric tetramers 222 (say, ConA), or 4 (e.g. Neuraminadase) in the literature. Peanut lectin had two dimers, each with a two-fold symmetry, but the two dimers were not related by mutually perpendicular two-fold axes (PNAS, 1994, vol 91, 227- 231).
Shekhar On Thu, Jul 29, 2010 at 1:05 PM, Vellieux Frederic <[email protected] > wrote: > Non-symmetric tetramers: you can check out Tete-Favier et al (1993), Acta > Cryst. D49, 246: the quaternary structure was assumed to have local 222 > symmetry. It turned out this was not exactly the case: the actual symmetry > of the object (the molecule) was "pseudo" 2t2t2t. So in addition to 2-fold > axes being common as an assembly mechanism (leading to the quite common 222 > symmetry) you can have deviations from this symmetry. > > Fred. > > Fred wrote: > >> Dear CCP4bb, >> Could someone please, point me to some references about non-symmetric >> tetramers? If I have a tetramer composed by 4 identical subunits, it'll >> always have a P4 point group symmetry? >> Thank in advance, >> Tomb >> >> >> -- Shekhar C. Mande Centre for DNA Fingerprinting and Diagnostics Bldg.7, Gruhakalpa 5-4-399/B, Nampally Hyderabad- 500001 INDIA Phone: +91-40-24749401 Fax: +91-40-24749448
