Complementation of an Escherichia coli DnaK Defect by Hsc70-DnaK Chimeric Proteins
Complementation of an Escherichia coli DnaK Defect by Hsc70-DnaK Chimeric Proteins
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DOI：
10.1128/jb.186.18.6248-6253.2004
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发表时间：
2004-09
影响因子：
3.2
通讯作者：
J. Suppini;Mouna Amor;J. Alix;M. Ladjimi
中科院分区：
文献类型：
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作者：
J. Suppini;Mouna Amor;J. Alix;M. Ladjimi
摘要大肠杆菌DNAK和大鼠Hsc70是高度保守的70 kDa热休克蛋白(Hsp70)家族成员，在与多肽和未折叠蛋白的相互作用以及与辅伴侣的协同作用方面表现出很强的序列和结构相似性以及相似的功能特性。我们在这里表明，虽然如预期的那样，DNAK蛋白能够补充E.ColiDNAK突变株在高温下生长和λ噬菌体繁殖，但Hsc70蛋白不能。然而，其中的肽结合结构域已经被DNAK取代的Hsc70能够补充该菌株的两种表型，这表明DNAK的肽结合结构域对于实现该蛋白在高温下生长和λ噬菌体复制所必需的特定功能是必不可少的。这些发现对Hsp70的功能特异性以及蛋白质-蛋白质相互作用在DNAK伴侣系统中的作用进行了讨论。
ABSTRACT Escherichia coli DnaK and rat Hsc70 are members of the highly conserved 70-kDa heat shock protein (Hsp70) family that show strong sequence and structure similarities and comparable functional properties in terms of interactions with peptides and unfolded proteins and cooperation with cochaperones. We show here that, while the DnaK protein is, as expected, able to complement an E. coli dnaK mutant strain for growth at high temperatures and λ phage propagation, Hsc70 protein is not. However, an Hsc70 in which the peptide-binding domain has been replaced by that of DnaK is able to complement this strain for both phenotypes, suggesting that the peptide-binding domain of DnaK is essential to fulfill the specific functions of this protein necessary for growth at high temperatures and for λ phage replication. The implications of these findings on the functional specificities of the Hsp70s and the role of protein-protein interactions in the DnaK chaperone system are discussed.