Biochemistry, Molecular Biology, Entomology, Plant Pathology, Mississippi State University, Mississippi, USA
Lysine 2-hydroxyisobutyrylation is a recently identified protein post-translational modification that is known to affect the association between histone and DNA. However, non-histone protein lysine 2-hydroxyisobutyrylation remain largely unexplored. Using antibody-based affinity enrichment of 2-hydroxyisobutyrylation peptides and nano-HPLC/MS/MS analysis, we identified 9,916 2-hydroxyisobutyryl lysine sites on 2,512 proteins in developing rice seeds, representing the first lysine 2-hydroxyisobutyrylome dataset. Functional annotation analyses indicated that a wide variety of vital biological processes were preferably targeted by lysine 2-hydroxyisobutyrylation, including glycolysis/gluconeogenesis, TCA cycle, starch biosynthesis, lipid metabolism, protein biosynthesis and processing. Our finding showed that most 2-hydroxyisobutyryl sites identified were unique to lysine 2-hydroxyisobutyrylation compared to lysine acetylation and succinylation, suggesting the existence of specific establishment mechanism and cellular functions of the 2-hydroxyisobutyrylated proteins. Analysis of the lysine 2-hydroxyisobutyrylation sites found that the modification sites were highly sequence specific and had less surface accessibility compared with other lysine residues. Our study provides the first systematic analysis of lysine 2-hydroxyisobutyrylation proteome and serves as an important resource for further investigation of the regulatory mechanisms and functions of lysine 2-hydroxyisobutyrylation.
Keywords: Posttranslational modification, seed developement, lysine 2-hydroxyisobutyrylation, rice.