The N-terminal signal sequence and the last 98 amino acids are not essential for the secretion of Bacillus sp TS-23 alpha-amylase in Escherichia coli

A truncated Bacillus sp. TS-23 alpha -amylase gene lacking 96 and 294 bp at its 5' and 3' end respectively was prepared by polymerase chain reaction and cloned into Escherichia coli expression vector, pQE-30, under the control of T5 promoter. SDS-PAGE and activity staining analyses showed that the His(6)-tagged amylase had a molecular mass of approximately 54 kDa. Isopropyl-beta -D-thiogalactopyranoside (IPTG) induction of E. coli M15 cells bearing the recombinant plasmid resulted in the extracellular production of active amylase. Western blot analysis also revealed that the truncated amylase was present in the periplasmic space and culture medium

Intelligent tracking control of a DC motor driver using self-organizing TSK type fuzzy neural networks

[[abstract]]In this paper, a self-organizing Takagi–Sugeno–Kang (TSK) type fuzzy neural network (STFNN) is proposed. The self-organizing approach demonstrates the property of automatically generating and pruning the fuzzy rules of STFNN without the preliminary knowledge. The learning algorithms not only extract the fuzzy rule of STFNN but also adjust the parameters of STFNN. Then, an adaptive self-organizing TSK-type fuzzy network controller (ASTFNC) system which is composed of a neural controller and a robust compensator is proposed. The neural controller uses an STFNN to approximate an ideal controller, and the robust compensator is designed to eliminate the approximation error in the Lyapunov stability sense without occurring chattering phenomena. Moreover, a proportional-integral (PI) type parameter tuning mechanism is derived to speed up the convergence rates of the tracking error. Finally, the proposed ASTFNC system is applied to a DC motor driver on a field-programmable gate array chip for low-cost and high-performance industrial applications. The experimental results verify the system stabilization and favorable tracking performance, and no chattering phenomena can be achieved by the proposed ASTFNC scheme.[[notice]]補正完畢[[incitationindex]]SCI[[booktype]]紙本[[booktype]]電子

Identification of essential histidine residues in a recombinant alpha-amylase of thermophilic and alkaliphilic Bacillus sp strain TS-23

To understand the structure-function relationships of a truncated Bacillus sp. strain TS-23 alpha-amylase, each of His-137, His-191, His-239, His-269, His-305, His-323, His-361, His-436, and His-475 was replaced with leucine. The molecular masses of the purified wild-type and mutant enzymes were approximately 54 kDa. The specific activity of His323Leu and His436Leu was decreased by more than 52%, while His239Leu, His305Leu, and His475Leu showed activity similar to that of the wild-type enzyme. As compared with the wild-type enzyme, His323Leu and His436Leu exhibited a 62% decrease in the value of k(cat)/K-m. Alterations in His-191, His-239, His-305, and His-475 did not cause a significant change in the K-m or k(cat) values. At 70degreesC, a decreased half-life was observed in His436Leu. These results indicate that His-137, His-269, and His-361 of Bacillus sp. strain TS-23 alpha-amylase are important for proper catalytic activity and that His-436 may contribute to the thermostability of the enzyme