The propensity of the peptide fragments 233-248, 245-260, 258-276, 279-298 and 299-316 from the t... more The propensity of the peptide fragments 233-248, 245-260, 258-276, 279-298 and 299-316 from the thermolysin C-terminal domain to form non-random structures has been examined by CD and two-dimensional NMR spectroscopy. The conformational properties of these fragments have been studied in aqueous solution and in the mixed solvent trifluoroethanol/H,O (3 : 7 by vol.). Small but detectable populations of helical structures (up to 10-20%) in aqueous solution have been found for the fragments 233-248,279-298 and 299-316. These populations are remarkably enhanced (50-70%) in the more hydrophobic mixed solvent, where the fragment 258-276 also forms a comparable helical population. These four fragments are helical in the native crystal structure and the spanning of the corresponding helices in the isolated peptides in solution matches very closely the ones in the native structure. In contrast, the fragment 245-260, an D-loop in the crystal, remains unstructured in both solvents. Medium-range NOE between protons in sidechains indicate the adoption of preferred sidechain conformations accompanying helix formation. Results are in agreement with the framework model of folding, in which native elements of secondary structure are formed first and folding follows from the collapse of these structural elements.
This paper presents the evaluation of the program Computers for Education. The program aims to in... more This paper presents the evaluation of the program Computers for Education. The program aims to integrate computers, donated by the private sector, into the teaching of language in public schools. The authors conduct a two-year randomized evaluation of the program using a sample of 97 schools and 5,201 children. Overall, the program seems to have had little effect on students' test scores and other outcomes. These results are consistent across grade levels, subjects, and This paper-a product of the Education Team, Human Development Network-is part of a larger effort the network to estimate the impact of Information and Communication Technologies on education. Policy Research Working Papers are also posted on the Web at http://econ.worldbank.org. The author may be contacted at [email protected].
The propensity of the peptide fragments 233-248, 245-260, 258-276, 279-298 and 299-316 from the t... more The propensity of the peptide fragments 233-248, 245-260, 258-276, 279-298 and 299-316 from the thermolysin C-terminal domain to form non-random structures has been examined by CD and two-dimensional NMR spectroscopy. The conformational properties of these fragments have been studied in aqueous solution and in the mixed solvent trifluoroethanol/H,O (3 : 7 by vol.). Small but detectable populations of helical structures (up to 10-20%) in aqueous solution have been found for the fragments 233-248,279-298 and 299-316. These populations are remarkably enhanced (50-70%) in the more hydrophobic mixed solvent, where the fragment 258-276 also forms a comparable helical population. These four fragments are helical in the native crystal structure and the spanning of the corresponding helices in the isolated peptides in solution matches very closely the ones in the native structure. In contrast, the fragment 245-260, an D-loop in the crystal, remains unstructured in both solvents. Medium-range NOE between protons in sidechains indicate the adoption of preferred sidechain conformations accompanying helix formation. Results are in agreement with the framework model of folding, in which native elements of secondary structure are formed first and folding follows from the collapse of these structural elements.
This paper presents the evaluation of the program Computers for Education. The program aims to in... more This paper presents the evaluation of the program Computers for Education. The program aims to integrate computers, donated by the private sector, into the teaching of language in public schools. The authors conduct a two-year randomized evaluation of the program using a sample of 97 schools and 5,201 children. Overall, the program seems to have had little effect on students' test scores and other outcomes. These results are consistent across grade levels, subjects, and This paper-a product of the Education Team, Human Development Network-is part of a larger effort the network to estimate the impact of Information and Communication Technologies on education. Policy Research Working Papers are also posted on the Web at http://econ.worldbank.org. The author may be contacted at [email protected].
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