Scorpion toxins are well-known as the largest potassium channel peptide blocker family. They have been successfully proven to be valuable molecular probes for structural research on diverse potassium channels. The potassium channel pore region, including the turret and filter regions, is the binding interface for scorpion toxins, and structural features from different potassium channels have been identified using different scorpion toxins. According to the spatial orientation of channel turrets with differential sequence lengths and identities, conformational changes and molecular surface properties, the potassium channel turrets can be divided into the following three states: open state with less hindering effects on toxin binding, half-open state or half-closed state with certain effects on toxin binding, and closed state with remarkable effects on toxin binding. In this review, we summarized the diverse structural features of potassium channels explored using scorpion toxin tools and discuss future work in the field of scorpion toxin-potassium channel interactions.

Ordinary screening of transfusion-transmissible infections (TTIs) among blood donors is essential for blood transfusion. Although there is several TTIs studies focus on human immunodeficiency virus, hepatitis B and C viruses, and Treponema pallidum infections in China, it is no data to illustrate any firm conclusion from Shiyan City, Central China. It aims to verify the seroprevalence of TTIs among blood donors at Shiyan. A retrospective analysis of blood donors’ information was conducted for the presence of HIV, HBV, HCV and T. pallidum. Logistic regression analysis was used to demonstrate risk factors including age, gender and occupation associated with them. The variation tendency in seroprevalence of these TTIs over the study period was evaluated by Cochran-Armitage trend test. Of 211 639 blood donors, 2 858 (1.35 %) had serological evidence of TTIs. The seroprevalence of HIV, HBV, HCV and T. pallidum were 0.08 %, 0.51 %, 0.20 % and 0.57 %, respectively. However, the co-infection prevalence of TTIs has not been detected. The HIV seropositivity significantly increased among female donors (OR = 1.63, P < 0.001) and farmers (OR = 2.02, P = 0.020). Significantly increased HBV seropositivity was only observed framers (OR = 1.87, P <0.001) compared to workers. Analogously, significantly increased HCV seropositivity was observed among farmers (OR = 2.59, P < 0.001), students (OR = 2.43, P < 0.001), merchants (OR = 1.70, P = 0.014) and others (OR = 1.78, P =0.001). The T. pallidum seroprevalence was notably increased among female (OR = 1.54, P < 0.001), and farmers (OR = 1.70, P <0.001). Moreover, significantly increasing trends of HIV (Z = −6.88, P < 0.01), HBV (Z = −4.52, P < 0.01), HCV (Z = −4.16, P < 0.01) and T. pallidum (Z = −1.36, P < 0.01) seropositivity were observed over the study period. It originally offers a substantial prevalence of TTIs among blood donors at Shiyan, Central China. Severe blood donor selection and all-inclusive screening of blood are highly recommended. It might be helpful for developing and updating guidance for blood safety. Retrospectively registered.

Defensins form a major family of antimicrobial peptides. Recently, human β‐defensin 2 and fungal plectasin were shown to be immune‐related potassium voltage‐gated channel subfamily A member 3 (Kv1.3) channel inhibitors. This work continued to show that the human α‐defensins human neutrophil peptide (HNP) 1 and human defensin (HD) 5 are selective Kv1.3 channel inhibitors with 50% inhibition concentration values of 102.0 ± 30.3 nM and 2.2 ± 0.2 μM, respectively. Furthermore, HNP1 was found to inhibit Kv1.3 currents and IL‐2 secretion in human CD3 ⁺ T cells. Despite the structural similarity between HNP1 and HD5, HNP1 could simultaneously bind to the S1‐S2 linker and the pore region of the Kv1.3 channel as both a toxinlike blocker and a novel modifier, whereas HD5 could only bind to the channel pore region as a toxinlike blocker. As a channel modifier, HNP1 could shift the conductance‐voltage relationship curve of the Kv1.3 channel by ∼9.5 mV in the positive direction and could increase the time constant for channel activation through the electrostatic repulsion between the cationic HNP1 anchored in the S1‐S2 linker and the positively charged S4 domain of the Kv1.3 channel. Together, these findings reveal that human α‐defensins are novel endogenous inhibitors of Kv1.3 channels with distinct interaction mechanisms, which facilitates future research into their adaptive immune functions.—Xie, Z., Feng, J., Yang, W., Xiang, F., Yang, F., Zhao, Y., Cao, Z., Li, W., Chen, Z., Wu, Y. Human α‐defensins are immune‐related Kv1.3 channel inhibitors: new support for their roles in adaptive immunity. FASEB J. 29, 4324‐4333 (2015). www.fasebj.org