Localization of Proteins to the 1,2-Propanediol Utilization Microcompartment by Non-native Signal Sequences Is Mediated by a Common Hydrophobic Motif
Localization of Proteins to the 1,2-Propanediol Utilization Microcompartment by Non-native Signal Sequences Is Mediated by a Common Hydrophobic Motif
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DOI：
10.1074/jbc.m115.651919
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发表时间：
2015-10-02
影响因子：
4.8
通讯作者：
Tullman-Ercek, Danielle
中科院分区：
文献类型：
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作者：
Jakobson, Christopher M.;Kim, Edward Y.;Tullman-Ercek, Danielle
各种细菌将代谢途径定位于称为细菌微区室 (MCP) 的蛋白质细胞器，使碳源的代谢能够增强肠道中的存活率和致病性。人们对利用细菌 MC:Ps 进行代谢工程应用非常感兴趣，但对 MCP 信号序列与不同 MCP 系统的蛋白质壳之间的相互作用知之甚少。我们发现乙醇胺利用（Eut）和甘氨酰自由基生成蛋白NICP的N端序列能够将报告蛋白靶向1,2-丙二醇利用（Pdu）MCP，并且这种定位是由保守的疏水残基基序介导的。通过添加单个氨基酸来概括该基序，赋予乙醇利用 MCP 系统的 N 端序列靶向功能，该序列以前不充当 Pdu 信号序列。此外，Pdu定位信号序列与天然Pdu靶向序列竞争封装在Pdu MCP中。肠沙门氏菌天然具有 Pdu 和 Eut 操纵子，我们的结果表明 Eut 蛋白可能在体内定位于 Pdu MCP。我们进一步证明，当 Pdu 酶被其 Eut 同系物取代时，肠沙门氏菌 I,T2 保留了以 1,2 丙二醇作为唯一碳源生长的能力。尽管这一发现与天然系统的相关性仍有待探索，但我们表明本文描述的 Pdu 定位信号序列允许控制封装在 Pdu MCP 内的异源蛋白的比例。
Various bacteria localize metabolic pathways to proteinaceous organelles known as bacterial microcompartments (MCPs), enabling the metabolism of carbon sources to enhance survival and pathogenicity in the gut. There is considerable interest in exploiting bacterial MC:Ps for metabolic engineering applications, but little is known about the interactions between MCP signal sequences and the protein shells of different MCP systems. We found that the N-terminal sequences from the ethanolamine utilization (Eut) and glycyl radical-generating protein NICPs are able to target reporter proteins to the 1,2-propanediol utilization (Pdu) MCP, and that this localization is mediated by a conserved hydrophobic residue motif. Recapitulation of this motif by the addition of a single amino acid conferred targeting function on an N-terminal sequence from the ethanol utilization MCP system that previously did not act as a Pdu signal sequence. Moreover, the Pdu-localized signal sequences competed with native Pdu targeting sequences for encapsulation in the Pdu MCP. Salmonella enterica natively possesses both the Pdu and Eut operons, and our results suggest that Eut proteins might be localized to the Pdu MCP in vivo. We further demonstrate that S. enterica I,T2 retained the ability to grow on 1,2propanediol as the sole carbon source when a Pdu enzyme was replaced with its Eut homolog. Although the relevance of this finding to the native system remains to be explored, we show that the Pdu-localized signal sequences described herein allow control over the ratio of heterologous proteins encapsulated within Pdu MCPs.