Molecular Replacement Studies of Cucurmosin from Cucurbita Moschata:Structure Homology with Trichosanthin

1 INTRODUCTION Many plants contain proteins that are capable of inactivating ribosomes and therefore are called ribosome-inactivating proteins or RIPs[1]. RIPs are RNA N-glycosidases that inactivate ribosomes through a site-specific deadenylation of the large ribosomal RNA[2, 3]. RIPs are also capable of inactivating many nonribosomal nucleic acid substrates and can be considered as polynucleotide: adenosine glycosidases[4～6]. There are two types of RIPs: type I, single chain pr…     

Crystallization and Preliminary Crystallographic Studies of Cucurmosin 2,a Ribosome-inactivating Protein from the Sarcocarp of Cucurbita moschata

Cucurmosin 2, a type 1 ribosome-inactivating protein （RIP） isolated from sarcocarp of Cucurbita moschata, has been crystallized by the vapor-diffusion method using PEG6000 as the precipitant. The crystals belong to the orthorhombic space group P212121, with unit cell parameters a = 55.853, b = 65.507, c = 91.754 А, and have one molecule per asymmetric unit. X-ray data have been collected to 1.8А, using a synchrotron source.     

平移在数学解题中的妙用——由一道中考压轴题的解法联想到

俗话说:"要给学生一杯水,教师要有一桶水."但是,如果教师有了一桶水,那么倒给学生那杯水时,怎样倒不至于把水倒出杯外?就要讲教学方法,即需要教学的艺术.现在有些老师在初中总复习时,为了对付中考的"压轴题",成了历年全国各地中考压轴题的"搬运工",把原题中的解答过程不假思索地抛给学生,使学生负担重,收效甚微,而且还不得要领.从这个意义上来讲,我们在数学总复习时对压轴题的解答要作一番分析和思