| Structural highlights
Disease
NAA20_HUMAN Autosomal recessive non-syndromic intellectual disability. The disease is caused by variants affecting the gene represented in this entry.
Function
NAA20_HUMAN Catalytic subunit of the NatB complex which catalyzes acetylation of the N-terminal methionine residues of peptides beginning with Met-Asp, Met-Glu, Met-Asn and Met-Gln (PubMed:34230638). Proteins with cell cycle functions are overrepresented in the pool of NatB substrates. Required for maintaining the structure and function of actomyosin fibers and for proper cellular migration.[1] [2]
Publication Abstract from PubMed
N-terminal acetylation is a chemical modification carried out by N-terminal acetyltransferases (NATs). A major member of this enzyme family, NatB, acts on much of the human proteome, including alpha-synuclein (alphaS), a synaptic protein that mediates vesicle trafficking. NatB acetylation of alphaS modulates its lipid vesicle binding properties and amyloid fibril formation, which underlies its role in the pathogenesis of Parkinson's disease. Although the molecular details of the interaction between human NatB (hNatB) and the N-terminus of alphaS have been resolved, whether the remainder of the protein plays a role in interacting with the enzyme is unknown. Here we execute the first synthesis, by native chemical ligation, of a bisubstrate inhibitor of NatB consisting of coenzyme A and full-length human alphaS, additionally incorporating two fluorescent probes for studies of conformational dynamics. We use cryo-electron microscopy (cryo-EM) to characterize the structural features of the hNatB/inhibitor complex and show that, beyond the first few residues, alphaS remains disordered when in complex with hNatB. We further probe changes in the alphaS conformation by single molecule Forster resonance energy transfer (smFRET) to reveal that the C-terminus expands when bound to hNatB. Computational models based on the cryo-EM and smFRET data help to explain the conformational changes and their implications for hNatB substrate recognition and specific inhibition of the interaction with alphaS. Beyond the study of alphaS and NatB, these experiments illustrate valuable strategies for the study of challenging structural biology targets through a combination of protein semi-synthesis, cryo-EM, smFRET, and computational modeling.
Semi-synthetic CoA-alpha-Synuclein Constructs Trap N-terminal Acetyltransferase NatB for Binding Mechanism Studies.,Pan B, Gardner S, Schultz K, Perez RM, Deng S, Shimogawa M, Sato K, Rhoades E, Marmorstein R, Petersson EJ bioRxiv. 2023 Apr 3:2023.04.03.535351. doi: 10.1101/2023.04.03.535351. Preprint. PMID:37066334[3]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
References
- ↑ Starheim KK, Arnesen T, Gromyko D, Ryningen A, Varhaug JE, Lillehaug JR. Identification of the human N(alpha)-acetyltransferase complex B (hNatB): a complex important for cell-cycle progression. Biochem J. 2008 Oct 15;415(2):325-31. PMID:18570629 doi:10.1042/BJ20080658
- ↑ Morrison J, Altuwaijri NK, Brønstad K, Aksnes H, Alsaif HS, Evans A, Hashem M, Wheeler PG, Webb BD, Alkuraya FS, Arnesen T. Missense NAA20 variants impairing the NatB protein N-terminal acetyltransferase cause autosomal recessive developmental delay, intellectual disability, and microcephaly. Genet Med. 2021 Nov;23(11):2213-2218. PMID:34230638 doi:10.1038/s41436-021-01264-0
- ↑ Pan B, Gardner S, Schultz K, Perez RM, Deng S, Shimogawa M, Sato K, Rhoades E, Marmorstein R, Petersson EJ. Semi-synthetic CoA-α-Synuclein Constructs Trap N-terminal Acetyltransferase NatB for Binding Mechanism Studies. bioRxiv. 2023 Apr 3:2023.04.03.535351. PMID:37066334 doi:10.1101/2023.04.03.535351
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