ST04. This enzyme shows smaller than 13% amino-acid sequence identity to other known alpha-amylases and displays a unique enzymatic property in that it hydrolyzes both alpha-1,4-glucosidic and alpha-1,6-glucosidic linkages of substrates, recognizing only maltose units, in an exo-type manner. Here, the
crystal structure of PSMA at a resolution of 1.8 angstrom is reported, showing a tight ring-shaped tetramer with monomers composed of two domains: an N-domain (amino acids 1-341) with a typical GH57 family (beta/alpha)(7)-barrel fold and a C-domain (amino acids 342-597) composed of alpha-helical bundles. A small closed cavity observed in proximity to the catalytic residues Glu153 and Asp253 at the domain interface has the appropriate volume and geometry to bind a maltose unit, accounting for the selective exo-type BI 6727 cell line maltose hydrolysis of the enzyme. A narrow gate at the putative subsite +1 formed by residue Phe218 and Phe452 is essential for specific cleavage of glucosidic bonds. The closed cavity at the active site is connected to a short substrate-binding channel that extends to the central hole of the tetramer, exhibiting a geometry that is significantly different from classical maltogenic amylases or beta-amylases.
The structural features of buy CCI-779 this novel exo-type maltose-forming alpha-amylase provide a molecular basis for its unique enzymatic characteristics and for its potential use in industrial applications and protein engineering.”
“The maintenance of information in auditory short-term memory (ASTM) is accompanied by a sustained anterior negativity
(SAN) in the event-related potential measured during the retention interval of simple auditory memory tasks. Previous work learn more on ASTM showed that the amplitude of the SAN increased in negativity as the number of maintained items increases. The aim of the current study was to measure the SAN and observe its behavior beyond the point of saturation of auditory short-term memory. We used atonal pure tones in sequences of 2, 4, 6, or 8 t. Our results showed that the amplitude of SAN increased in negativity from 2 to 4 items and then levelled off from 4 to 8 items. Behavioral results suggested that the average span in the task was slightly below 3, which was consistent with the observed plateau in the electrophysiological results. Furthermore, the amplitude of the SAN predicted individual differences in auditory memory capacity. The results support the hypothesis that the SAN is an electrophysiological index of brain activity specifically related to the maintenance of auditory information in ASTM. (C) 2014 Elsevier B.V. All rights reserved.”
“Background The durability of Long Lasting Insecticidal Nets (LLINs) in field conditions is of great importance for malaria prevention and control efforts; however, the physical integrity of the net fabric is not well understood making it challenging to determine overall effectiveness of nets as they age.