Nablo Brian J, Halverson Kelly M, Robertson Joseph W F, Nguyen Tam L, Panchal Rekha G, Gussio Rick, Bavari Sina, Krasilnikov Oleg V, Kasianowicz John J
Electrical and Electronics Laboratory, Semiconductor Electronics Division, National Institute of Standards and Technology, Gaithersburg, Maryland 20899-8120, USA.
Biophys J. 2008 Aug;95(3):1157-64. doi: 10.1529/biophysj.107.121715.
Nonelectrolyte polymers of poly(ethylene glycol) (PEG) were used to estimate the diameter of the ion channel formed by the Bacillus anthracis protective antigen 63 (PA(63)). Based on the ability of different molecular weight PEGs to partition into the pore and reduce channel conductance, the pore appears to be narrower than the one formed by Staphylococcus aureus alpha-hemolysin. Numerical integration of the PEG sample mass spectra and the channel conductance data were used to refine the estimate of the pore's PEG molecular mass cutoff (approximately 1400 g/mol). The results suggest that the limiting diameter of the PA(63) pore is <2 nm, which is consistent with an all-atom model of the PA(63) channel and previous experiments using large ions.
聚乙二醇（PEG）的非电解质聚合物被用于估算炭疽芽孢杆菌保护性抗原63（PA(63)）形成的离子通道直径。基于不同分子量PEG进入孔道并降低通道电导率的能力，该孔道似乎比金黄色葡萄球菌α-溶血素形成的孔道更窄。对PEG样品质谱和通道电导率数据进行数值积分，以优化对孔道PEG分子量截止值（约1400 g/mol）的估计。结果表明，PA(63)孔道的极限直径小于2 nm，这与PA(63)通道的全原子模型以及先前使用大离子的实验结果一致。
