Position of Proline Mediates the Reactivity of S-Palmitoylation
Position of Proline Mediates the Reactivity of S-Palmitoylation
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DOI：
10.1021/acschembio.5b00429
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发表时间：
2015-11-01
影响因子：
4
通讯作者：
Mukhopadhyay, Suchetana
中科院分区：
文献类型：
--
作者：
Khanal, Neelam;Pejaver, Vikas;Mukhopadhyay, Suchetana
Palmitoylation, a post-translational modification in which a saturated 16-carbon chain is added predominantly to a cystein residue, participates in various biological functions. The position of proline relative to other residues being post-translationally modified has been previously reported as being important.. We determined that proline is statistically enriched around cysteines known to be S-palmitoylated. The goal of this work was to determine how the position of proline influences the palmitoylation of the cysteine residue. We established a mass spectrometry-based approach to investigate time- and temperature-dependent kinetics of autopalmitoylation in vitro and to derive the thermodynamic parameters of the transition state associated with palmitoylation; to the best of our knowledge, our work is the first to study the kinetics and activation properties of the palmitoylation process. We then used these thermochemical parameters to determine if the position of proline relative to the modified cysteine is important for palmitoylation. Our results show that peptides with, proline at the 1 position of cysteine in their sequence (PC) have lower enthalpic barriers and higher entropic barriers in comparison to the same peptides with proline at the +1 position of cysteine (CP) interestingly, the free-energy barriers for both pairs are almost identical. Molecular dynamics studies demonstrate that the flexibility of the cysteine backbone in the PC containing peptide when compared to the CP-containing peptide explains the incased entropic barrier and decreased enthalpic barrier observed experimentally.
