The permeabilized SecY protein-translocation channel can serve as a nonspecific sugar transporter

Sen Mei; Chong Xie; Hao Mi; Chuang Xue; Qiang Guo; Guang-Qing Du; Guo-Bei Li; Cai-Xia Li; Ya-Nan Qu; Ming-Hao Xiong; Yang Jiang; Tian-Wei Tan; Shang-Tian Yang; Li-Hai Fan

The copyright holder for this preprint (which was not peer-reviewed) is the author/funder. . https://doi.org/10.1101/378786 doi: bioRxiv preprint 4 sugars are transported passively, no sugars are known to enter cells via a free diffusion 56 manner (Romano, 1986) . 57 The protein translocation channel is a structurally conserved protein-conducting 58 system that allows polypeptides to be transferred across or integrated into cell membranes 59 (Osborne et al, 2005; Rapoport, 2007; Mandon et al, 2009 ). In bacteria, this channel is 60 formed by the SecY complex (SecYEG) and is located in the plasma membrane 61 (Brundage et al, 1990; Akimaru et al, 1991; Breyton et al, 2002) . The X-ray crystal 62 structure revealed that the SecY channel has an hourglass shape with a narrow central 63 constriction consisting of six hydrophobic amino acid residues termed the pore ring, and (Kornberg et al, 2000) , these 74 findings prompted us to hypothesize that whether the SecY channel can be designed as a 75 free diffusion passageway for efficient transport of carbohydrates, thus developing an 76 entirely novel paradigm for sugar passage and addressing the problems encountered with 77 the specific transporters. In the present work, we engineered the SecY channel by plug 78 All rights reserved. No reuse allowed without permission.