4nw2
Tandem chromodomains of human CHD1 in complex with Influenza virus NS1 C-terminal tail trimethylated at K229
Structural highlights
FunctionCHD1_HUMAN ATP-dependent chromatin-remodeling factor which functions as substrate recognition component of the transcription regulatory histone acetylation (HAT) complex SAGA. Regulates polymerase II transcription. Also required for efficient transcription by RNA polymerase I, and more specifically the polymerase I transcription termination step. Regulates negatively DNA replication. Not only involved in transcription-related chromatin-remodeling, but also required to maintain a specific chromatin configuration across the genome. Is also associated with histone deacetylase (HDAC) activity (By similarity). Required for the bridging of SNF2, the FACT complex, the PAF complex as well as the U2 snRNP complex to H3K4me3. Functions to modulate the efficiency of pre-mRNA splicing in part through physical bridging of spliceosomal components to H3K4me3. Required for maintaining open chromatin and pluripotency in embryonic stem cells.[1] Publication Abstract from PubMedPathogens can interfere with vital biological processes of their host by mimicking host proteins. The NS1 protein of the influenza A H3N2 subtype possesses a histone H3K4-like sequence at its carboxyl terminus and has been reported to use this mimic to hijack host proteins. However, this mimic lacks a free N-terminus that is essential for binding to many known H3K4 readers. Here we show that the double chromodomains of CHD1 adopt an 'open pocket' to interact with the free N-terminal amine of H3K4, and the open pocket permits the NS1 mimic to bind in a distinct conformation. We also explored the possibility that NS1 hijacks other cellular proteins and found that the NS1 mimic has access to only a subset of chromatin-associated factors, such as WDR5. Moreover, methylation of the NS1 mimic can not be reversed by the H3K4 demethylase LSD1. Overall, we thus conclude that the NS1 mimic is an imperfect histone mimic. Structural basis for histone mimicry and hijacking of host proteins by influenza virus protein NS1.,Qin S, Liu Y, Tempel W, Eram MS, Bian C, Liu K, Senisterra G, Crombet L, Vedadi M, Min J Nat Commun. 2014 May 23;5:3952. doi: 10.1038/ncomms4952. PMID:24853335[2] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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