PDF(Pubmed)
Abstract：
Heat stress can cause cell death by triggering the aggregation of essential proteins. In bacteria, aggregated proteins are rescued by the canonical Hsp70/AAA+ (ClpB) bi-chaperone disaggregase. Man-made, severe stress conditions applied during, e.g., food processing represent a novel threat for bacteria by exceeding the capacity of the Hsp70/ClpB system. Here, we report on the potent autonomous AAA+ disaggregase ClpL from Listeria monocytogenes that provides enhanced heat resistance to the food-borne pathogen enabling persistence in adverse environments. ClpL shows increased thermal stability and enhanced disaggregation power compared to Hsp70/ClpB, enabling it to withstand severe heat stress and to solubilize tight aggregates. ClpL binds to protein aggregates via aromatic residues present in its N-terminal domain (NTD) that adopts a partially folded and dynamic conformation. Target specificity is achieved by simultaneous interactions of multiple NTDs with the aggregate surface. ClpL shows remarkable structural plasticity by forming diverse higher assembly states through interacting ClpL rings. NTDs become largely sequestered upon ClpL ring interactions. Stabilizing ring assemblies by engineered disulfide bonds strongly reduces disaggregation activity, suggesting that they represent storage states.
摘要：
热应激可通过引发必需蛋白质的聚集而导致细胞死亡。在细菌中，聚集的蛋白质被典型的Hsp70/AAA+(ClpB)双伴侣解聚酶拯救。人造的,期间施加的严重应力条件，例如，通过超过Hsp70/ClpB系统的容量，食品加工对细菌构成了新的威胁。这里,我们报道了来自单核细胞增生李斯特菌的有效的自主AAA+解聚酶ClpL,该酶可增强对食源性病原体的耐热性,从而能够在不利环境中持续存在.与Hsp70/ClpB相比，ClpL显示出增加的热稳定性和增强的解聚能力，使其能够承受严重的热应力并溶解紧密的聚集体。ClpL通过其N末端结构域(NTD)中存在的芳香族残基结合蛋白质聚集体,所述芳香族残基采用部分折叠和动态构象。靶标特异性通过多个NTD与聚集体表面的同时相互作用来实现。ClpL通过相互作用的ClpL环形成各种更高的组装态，从而显示出显着的结构可塑性。NTDs在ClpL环相互作用后大量隔离。通过工程二硫键稳定环组装体强烈降低解聚活性，表明它们代表存储状态。
