The Structural Basis of T4 Phage Lysis Control: DNA as the Signal for Lysis Inhibition

JOURNAL OF MOLECULAR BIOLOGY

卷:432

Article

Krieger, Inna, V¹  Kuznetsov, Vladimir^1,3  Chang, Jeng-Yih^1,2  Zhang, Junjie^1,2  Moussa, Samir H.^1,2,4  Young, Ryland F.^1,2  Sacchettini, James C.¹ 

[1] Texas A&M Univ, Dept Biochem & Biophys, 301 Old Main Dr, College Stn, TX 77843 USA

[2] Ctr Phage Technol, Dept Biochem & Biophys, College Stn, TX USA

[3] KBI Biopharma, 2 Triangle Dr, Res Triangle Pk, NC 27709 USA

[4] Boston BioHub, Entasis Therapeut, 35 Gatehouse Dr, Waltham, MA 02451 USA

关键词: lysis;    holin;    antiholin;    SAR domain;    domain swapping;   

DOI  :  10.1016/j.jmb.2020.06.013

来源: Elsevier

【 摘 要 】

Optimal phage propagation depends on the regulation of the lysis of the infected host cell. In T4 phage infection, lysis occurs when the holin protein (T) forms lesions in the host membrane. However, the lethal function of T can be blocked by an antiholin (RI) during lysis inhibition (LIN). LIN sets if the infected cell undergoes superinfection, then the lysis is delayed until host/phage ratio becomes more favorable for the release of progeny. It has been thought that a signal derived from the superinfection is required to activate RI. Here we report structures that suggest a radically different model in which RI binds to T irrespective of superinfection, causing it to accumulate in a membrane as heterotetrameric 2RI-2T complex. Moreover, we show the complex binds non-specifically to DNA, suggesting that the gDNA from the superinfecting phage serves as the LIN signal and that stabilization of the complex by DNA binding is what defines LIN. Finally, we show that soluble domain of free RI crystallizes in a domain-swapped homotetramer, which likely works as a sink for RI molecules released from the RI-T complex to ensure efficient lysis. These results constitute the first structural basis and a new model not only for the historic LIN phenomenon but also for the temporal regulation of phage lysis in general. (C) 2020 The Author(s). Published by Elsevier Ltd.

【 授权许可】

Free