Solute Carriers (SLC) superfamily is one of the most important membrane transporter families in the cell membrane (including intracellular membrane) of human,it is involved in some essential physiological functions such as intercellular substance transporting,energy transfer,nutrition and metabolism,signal transduction and so on.Solute Carriers (SLC) superfamily contains 52 subfamilies,with more than 400 members.Studies have shown that abnormal protein expression or functional defects of SLC caused by human genetic mutations are closely related with a variety of serious diseases such as diabetes,hypertension and depression,so the function research of SLC had attracted much attention in recent years.The known three-dimensional structures of SLC transporters help to explain the precise molecular mechanism of substrate binding and transporting,it provides a fine structure basis to study the molecular mechanism of related diseases and structure-based drug discovery.In this review,we summarized the progress on the structure and function of SLC superfamily transporters of late years,try to provide some common rules of SLC superfamily transporters.

Objective To investigate the role of the combination of alpha2-heremans-schmid glycoprotein (AHSG) , tumor necrosis factor-α (TNF-α) , and interleukin-1 β (IL-1β) in detecting carotid vulnerable plaque in patients with acute cerebral infarction (ACI). Methods A total of 136 ACI patients were enrolled. According to the carotid ultrasound results, patients were assigned into the stable plaque group (n = 57) and vulnerable plaque group (n = 79). And their clinical data were collected. Logistic regression analyses were performed to identify independent risk factors of carotid vulnerable plaque in ACI patients. Receiver operating characteristic (ROC) was used to explore the diagnostic efficacy of AHSG, TNF-α, IL-1β and their combination in detecting carotid vulnerable plaque. Results (1) AHSG level of vulnerable plaque group was significantly lower than that of stable plaque group (P < 0.05) , while the levels of TNF-α and IL-1β of vulnerable plaque group were higher than those of stable plaque group. (2) Multivariate logistic regression analyses revealed that hypertension (OR = 1.257, 95％CI: 1.017～ 1.554) , type 2 diabetes (OR=1.474, 95％ CI: 1.048 ～2.074) , AHSG (OR= 0.510, 95％ CI:0.287 ～0.920) , TNF-α (OR = 1.020, 95％CI: 1.006 ～1.029) and IL-1β (OR= 1.484, 95％CI: 1.067 ～2.062) were independent risk factors of carotid vulnerable plaque. (3) ROC curves revealed that the area under the curve (AUC) of AHSG combined with TNF-α and IL-1β detecting carotid vulnerable plaque was 0.903 (95％CI: 0.840～0.947) , with sensitivity of 89.87％ and specificity of 75.44％, which was significantly superior to that of three individual biomarker (P < 0.05). Conclusions AHSG, TNF-α and IL-1β are independent risk factors of carotid vulnerable plaque in ACI patients, and their combination has the highest predictive efficacy which is of high clinical significance.

We studied the mutation effect of subsites -3(Lys47), -7(146-152), and cyclization center (Tyr195) in active domain on product specificity of alpha-cyclodextrin glucanotransferase (alpha-CGTase) from Paenibacillus macerans sp. 602-1. The Lys47 was replaced by Thr47 and Tyr195 by Ile195, and the amino acids from 146 to 152 were replaced by Ile (named as delta6). All these mutant alpha-CGTases were actively expressed in E. coli BL21. Compared with the wild-type alpha-CGTase, the starch-degrading activities of all the mutant enzymes were declined. For mutant Y195I, the percentage of alpha-CD was decreased from 68% to 30%, and beta-CD was raised from 22.2% to 33.3%. Interestingly, gamma-CD was increased from 8.9% to 36.7% and became the main product, while the actual yield was increased from 0.4 g/L to 1.1 g/L. Mutant K47T and delta6 still produced alpha-CD as main product though the percentage of beta- and gamma-CD increased. Purified Y195I CGTase showed similar optimum temperature with the wild-type alpha-CGTase, but its optimum pH shifted from 5.0 to 6.0 with better pH stability. In summary, mutant Y195I CGTase has the potential to produce gamma-CD as the main product.
Escherichia coli ; genetics ; metabolism ; Glucosyltransferases ; genetics ; metabolism ; Mutant Proteins ; genetics ; metabolism ; Mutation ; Paenibacillus ; enzymology ; Recombinant Proteins ; genetics ; gamma-Cyclodextrins ; metabolism