tailieunhanh - A biophysical elucidation for less toxicity of Agglutinin than Abrin-a from the Seeds of Abrus Precatorius in consequence of crystal structure

Abstract X-ray crystal structure determination of agglutinin from abrus precatorius in Taiwan is presented. The crystal structure of agglutinin, a type II ribosome-inactivating protein (RIP) from the seeds of Abrus precatorius in Taiwan, has been determined from a novel crystalline form by the molecular replacement method using the coordinates of abrin-a as the template. The structure has space group P41212 with Z = 8, and been refined at Å to R-factor of . The rootmean-square deviations of bond lengths and angles from the standard values are Å and °. Primary, secondary, tertiary and quaternary structures of agglutinin have. | Cheng et al. Journal of Biomedical Science 2010 17 34 http content 17 1 34 a NSC The cost of publication In Journal of Blomodlcal Science Is bome by the National Science Council Taiwan JOURNAL OF BIOMEDICAL SCIENCE RESEARCH Open Access A biophysical elucidation for less toxicity of Agglutinin than Abrin-a from the Seeds of Abrus Precatorius in consequence of crystal structure Jack Cheng 1 Tian-Huey Lu 1 Chao-Lin Liu2 and Jung-Yaw Lin3 Abstract X-ray crystal structure determination of agglutinin from abrus precatorius in Taiwan is presented. The crystal structure of agglutinin a type II ribosome-inactivating protein RIP from the seeds of Abrus precatorius in Taiwan has been determined from a novel crystalline form by the molecular replacement method using the coordinates of abrin-a as the template. The structure has space group P41212 with Z 8 and been refined at Ằ to R-factor of . The rootmean-square deviations of bond lengths and angles from the standard values are Ằ and . Primary secondary tertiary and quaternary structures of agglutinin have been described and compared with those of abrin-a to a certain extent. In subsequent docking research we found that Asn200 of abrin-a may form a critical hydrogen bond with G4323 of 28SRNA while corresponding Pro199 of agglutinin is a kink hydrophobic residue bound with the cleft in a more compact complementary relationship. This may explain the lower toxicity of agglutinin than abrin-a despite of similarity in secondary structure and the activity cleft of two RIPs. Background Ribosome inactivating proteins RIPs are enzymes that can inactivate ribosomes. The molecular mechanism of inhibitory effect on protein synthesis has been shown that RIPs act as a RNA N-glycosidase hydrolyzing the C-N glycosidic bond of the adenosine residue at position 4324 in rat 28S rRNA 1 2 . They can cleave the synthetic RNA structure having a short double-helical stem and a loop containing a centered GAGA .