Activation and competition of lipoylation of H protein and its hydrolysis in a reaction cascade catalyzed by the multifunctional enzyme lipoate–protein ligase A

Publikationstyp
Journal Article
Publikationsdatum
2020-12
Sprache
English
Author
Zhang, Xinyi 
Nie, Jinglei 
Zheng, Yuanmin 
Ren, Jie 
Zeng, An-Ping orcid-logo
Institut
Bioprozess- und Biosystemtechnik V-1 
TORE-URI
http://hdl.handle.net/11420/7725
Enthalten in
Biotechnology and Bioengineering 
Volume
117
Issue
12
Start Page
3677
End Page
3687
Citation
Biotechnology and Bioengineering 117 (12): 3677-3687 (2020-12)
Publisher DOI
10.1002/bit.27526
Scopus ID
2-s2.0-85089474990
PubMed ID
32749694
Protein lipoylation is essential for the function of many key enzymes but barely studied kinetically. Here, the two-step reaction cascade of H protein lipoylation catalyzed by the multifunctional enzyme lipoate–protein ligase A (LplA) was quantitatively and differentially studied. We discovered new phenomena and unusual kinetics of the cascade: (a) the speed of the first reaction is faster than the second one by two orders of magnitude, leading to high accumulation of the intermediate lipoyl-AMP (Lip-AMP); (b) Lip-AMP is hydrolyzed, but only significantly at the presence of H protein and in competition with the lipoylation; (c) both the lipoylation of H protein and its hydrolysis is enhanced by the apo and lipoylated forms of H protein and a mutant without the lipoylation site. A conceptual mechanistic model is proposed to explain these experimental observations in which conformational change of LplA upon interaction with H protein and competitive nucleophilic attacks play key roles.
Schlagworte
H protein
hydrolysis
lipoate–protein ligase A
lipoylation
protein interaction