TASK DEFINITION: Given a question and a context passage, generate the answer having the word or phrase from the context passage. Here, the answer should be a shortest continous span from the passage.
PROBLEM: Context: Previous X-ray crystal structures have shown that linkers of five amino acid residues connecting pairs of chicken brain alpha-spectrin and human erythroid beta-spectrin repeats can undergo bending without losing their alpha-helical structure. To test whether bending at one linker can influence bending at an adjacent linker, the structures of two and three repeat fragments of chicken brain alpha-spectrin have been determined by X-ray crystallography. The structure of the three-repeat fragment clearly shows that bending at one linker can occur independently of bending at an adjacent linker. This observation increases the possible trajectories of modeled chains of spectrin repeats. Furthermore, the three-repeat molecule crystallized as an antiparallel dimer with a significantly smaller buried interfacial area than that of alpha-actinin, a spectrin-related molecule, but large enough and of a type indicating biological specificity. Comparison of the structures of the spectrin and alpha-actinin dimers supports weak association of the former, which could not be detected by analytical ultracentrifugation, versus strong association of the latter, which has been observed by others. To correlate features of the structure with solution properties and to test a previous model of stable spectrin and dystrophin repeats, the number of inter-helical interactions in each repeat of several spectrin structures were counted and compared to their thermal stabilities. Inter-helical interactions, but not all interactions, increased in parallel with measured thermal stabilities of each repeat and in agreement with the thermal stabilities of two and three repeats and also partial repeats of spectrin.
Question: Alpha-spectrin and beta-spectrin subunits form parallel or antiparallel heterodimers?

SOLUTION: antiparallel

PROBLEM: Context: The apolipoprotein E type 4 allele is a susceptibility gene for late-onset Alzheimer's disease. Apolipoprotein E is found in neurons, some of which contain paired helical filaments made of the microtubule-associated protein tau. Previous studies have demonstrated that the apoE3 isoform, but not the apoE4 isoform, binds tau with high avidity. Because the microtubule-associated protein MAP2c also effects microtubule assembly and stability, we examined interactions between apoE isoforms and MAP2c. Similar to the tau-binding results, apoE3, but not apoE4, bound MAP2c. Binding was detectable down to 10(-9) M MAP2c and 10(-8) M apoE3. Isoform-specific interactions of apoE with the microtubule-associated proteins MAP2c and tau might affect intracellular maintenance of microtubules and could contribute to a time-dependent pathogenesis of Alzheimer's disease.
Question: Which ApoE isoform is associated with atherosclerosis and Alzheimer's disease?

SOLUTION: apoe4 isoform

PROBLEM: Context: The general Chinese history texts on the Ming Dynasty, including the Mingdai Shi and the Mingshi, briefly mention Cao Qin's failed coup of 1461. Cao Qin's coup and the events leading up to it were covered in Gao Dai's Hong you lu of 1573, Jiao Hong's Guochao Xianzheng lu of 1594-1616, the Huang Ming shi gai of 1632 and the Mingshi jishi benmo of 1658. Li Xian also wrote about Cao Jixiang's career in his "Cao Jixiang zhi bian," featured in the Huang Ming mingchen jingji lu that was edited by Huang Xun in 1551.
Question: What happened second: Jiao Hong's Guochao Xianzheng lu or Huang Ming shi gai?

SOLUTION:
huang ming shi gai