No abstract

No abstract

Acylpeptide hydrolases (APHs) catalyze the removal of N-acylated amino acids from blocked peptides. Like other prolyloligopeptidase (POP) family members, APHs are believed to be important targets for drug design. To date, the binding pose of organophosphorus (OP) compounds of APH, as well as the different OP compounds binding and inducing conformational changes in two domains, namely, α/β hydrolase and β-propeller, remain poorly understood. We report a computational study of APH bound to chlorpyrifosmethyl oxon and dichlorvos. In our docking study, Val471 and Gly368 are important residues for chlorpyrifosmethyl oxon and dichlorvos binding. Molecular dynamics simulations were also performed to explore the conformational changes between the chlorpyrifosmethyl oxon and dichlorvos bound to APH, which indicated that the structural feature of chlorpyrifosmethyl oxon binding in APH permitted partial opening of the β-propeller fold and allowed the chlorpyrifosmethyl oxon to easily enter the catalytic site. These results may facilitate the design of APH-targeting drugs with improved efficacy.

No abstract

Composite structures with complex curved surface are typical important external structures of aircraft. Residual strain will be formed due to complex manufacturing processes, resulting in the weakness of structural strength. In addition, there are great security implications that various mechanisms used for aircraft safety may cause failures on service, such as fiber fracture, matrix cracking, stratification, and debonding. In this article, methods of structural state sensing on composite structures with complex curved surface are researched. This article established a method of strain monitoring on composite structures and strategy of damage identification based on distributed optical fiber sensors. First, strategies of high spatial resolution strain measurement are studied, and the criteria of damage identification on composite laminates based on strain information are deduced, which could be used on accurate positioning of crack tips. Finally, strain measurement and damage identification tests of composite structures with complex curved surface under uniform load condition were conducted. The results indicate that the distributed optical fiber sensor installed on the composite structures with complex curved surface can be used to measure strain precisely and identify damage in the neighborhood of fiber installation path accurately.