Capsid Structure of a Freshwater Cyanophage Siphoviridae Mic1

Hua Jin; Yong-Liang Jiang; Feng Yang; Jun-Tao Zhang; Wei-Fang Li; Ke Zhou; Jue Ju; Yuxing Chen; Cong-Zhao Zhou

doi:10.1016/j.str.2019.07.003

Capsid Structure of a Freshwater Cyanophage Siphoviridae Mic1

Structure. 2019 Oct 1;27(10):1508-1516.e3. doi: 10.1016/j.str.2019.07.003. Epub 2019 Aug 1.

Authors

Hua Jin¹, Yong-Liang Jiang¹, Feng Yang¹, Jun-Tao Zhang¹, Wei-Fang Li¹, Ke Zhou¹, Jue Ju¹, Yuxing Chen², Cong-Zhao Zhou³

Affiliations

¹ Hefei National Laboratory for Physical Sciences at the Microscale and School of Life Sciences, University of Science and Technology of China, Hefei, Anhui 230026, China.
² Hefei National Laboratory for Physical Sciences at the Microscale and School of Life Sciences, University of Science and Technology of China, Hefei, Anhui 230026, China. Electronic address: cyxing@ustc.edu.cn.
³ Hefei National Laboratory for Physical Sciences at the Microscale and School of Life Sciences, University of Science and Technology of China, Hefei, Anhui 230026, China. Electronic address: zcz@ustc.edu.cn.

PMID: 31378451
DOI: 10.1016/j.str.2019.07.003

Abstract

Cyanobacteria are the most abundant photosynthetic microorganisms, the global distribution of which is mainly regulated by the corresponding cyanophages. A systematic screening of water samples in the Lake Chaohu enabled us to isolate a freshwater siphocyanophage that infects Microcystis wesenbergii, thus termed Mic1. Using cryoelectron microscopy, we solved the 3.5-Å structure of Mic1 capsid. The major capsid protein gp40 of an HK97-like fold forms two types of capsomers, hexons and pentons. The capsomers interact with each other via the interweaved N-terminal arms of gp40 in addition to a tail-in-mouth joint along the three-fold symmetric axis, resulting in the assembly of capsid in a mortise-and-tenon pattern. The novel-fold cement protein gp47 sticks at the two-fold symmetric axis and further fixes the capsid. These findings provide structural insights into the assembly of cyanophages, and set up a platform to explore the mechanism of specific interactions and co-evolution with cyanobacteria.

Keywords: capsid assembly; cement protein; cryo-EM structure; cyanophage.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Capsid Proteins / chemistry*
Capsid Proteins / metabolism*
Cryoelectron Microscopy
Microcystis / virology*
Models, Molecular
Protein Conformation
Protein Domains
Protein Folding
Protein Multimerization
Siphoviridae / chemistry
Siphoviridae / metabolism*

Substances

Capsid Proteins

Supplementary concepts

Microcystis wesenbergii