1tr0
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(New page: 200px<br /><applet load="1tr0" size="450" color="white" frame="true" align="right" spinBox="true" caption="1tr0, resolution 1.80Å" /> '''Crystal Structure of...)
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Revision as of 00:28, 25 November 2007
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Crystal Structure of a boiling stable protein SP1
Overview
We previously reported on a new boiling stable protein isolated from aspen, plants (Populus tremula), which we named SP1. SP1 is a stress-related, protein with no significant sequence homology to other stress-related, proteins. It is a 108-amino-acid hydrophilic polypeptide with a molecular, mass of 12.4 kDa (Wang, W. X., Pelah, D., Alergand, T., Shoseyov, O., and, Altman, A. (2002) Plant Physiol. 130, 865-875) and is found in an, oligomeric form. Preliminary electron microscopy studies and, matrix-assisted laser desorption ionization time-of-flight mass, spectrometry experiments showed that SP1 is a dodecamer composed of two, stacking hexamers. We performed a SDS-PAGE analysis, a differential, scanning calorimetric study, and crystal structure determination to, further characterize SP1. SDS-PAGE indicated a spontaneous assembly of SP1, to one stable oligomeric form, a dodecamer. Differential scanning, calorimetric showed that SP1 has high thermostability i.e. Tm of 107, degrees C (at pH 7.8). The crystal structure of SP1 was initially, determined to 2.4 A resolution by multi-wavelength anomalous dispersion, method from a crystal belonging to the space group I422. The phases were, extended to 1.8 A resolution using data from a different crystal form, (P21). The final refined molecule includes 106 of the 108 residues and 132, water molecules (on average for each chain). The R-free is 20.1%. The, crystal structure indicated that the SP1 molecule has a ferredoxin-like, fold. Strong interactions between each two molecules create a stable, dimer. Six dimers associate to form a ring-like-shaped dodecamer strongly, resembling the particle visualized in the electron microscopy studies. No, structural similarity was found between the crystal structure of SP1 and, the crystal structure of other stress-related proteins such as small heat, shock proteins, whose structure has been already determined. This, structural study further supports our previous report that SP1 may, represent a new family of stress-related proteins with high, thermostability and oligomerization.
About this Structure
1TR0 is a Single protein structure of sequence from Populus tremula with GOL as ligand. Full crystallographic information is available from OCA.
Reference
The structural basis of the thermostability of SP1, a novel plant (Populus tremula) boiling stable protein., Dgany O, Gonzalez A, Sofer O, Wang W, Zolotnitsky G, Wolf A, Shoham Y, Altman A, Wolf SG, Shoseyov O, Almog O, J Biol Chem. 2004 Dec 3;279(49):51516-23. Epub 2004 Sep 14. PMID:15371455
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