Transient interaction of cpSRP54 with elongating nascent chains of the chloroplast‐encoded D1 protein; ‘cpSRP54 caught in the act’

FEBS Letters

Nilsson, Robert¹  van Wijk, Klaas Jan¹ 

[1] Department of Plant Biology, Cornell University, Emerson Hall, Ithaca, NY 14853, USA

关键词: cpSRP54;    Chloroplast;    D1 protein;    Translation;    Cross-linking;    SRP;    signal recognition particle;    TM;    transmembrane domain;    cp;    chloroplast;    RNC;    ribosome nascent chain;   

DOI  :  10.1016/S0014-5793(02)03016-8

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

The signal recognition particle (SRP) in bacteria and endoplasmic reticulum is involved in co-translational targeting. Plastids contain cpSRP54 and cpSRP43, unique to plants, but lack a SRP RNA molecule. A role for cpSRP in biogenesis of plastid-encoded membrane proteins has not been firmly established yet. In this study, a transient interaction between cpSRP54 and elongating D1 protein was observed using a homologous chloroplast translation system. Using the novel approach of cross-linking at different time points during elongation of full-length D1 protein, we showed that cpSRP54 interacts strongly with the elongating nascent chain forming two distinct cross-linked products. However, this interaction did not lead to an elongation arrest and cpSRP54 was released from the nascent chains, once they were longer than ∼14 kDa. Detailed mutant analysis showed that the cpSRP54 interaction occurred via the first transmembrane domain, which could be replaced by other hydrophobic domains of more than 10 amino acids.

【 授权许可】

Unknown