Abstract:
:The dynamical behavior of biomacromolecules is a fundamental property regulating a large number of biological processes. Protein dynamics have been widely shown to play a role in enzyme catalysis; however, the interplay between substrate dynamics and enzymatic activity is less understood. We report insights into the role of dynamics of substrates in the enzymatic activity of PME from Erwinia chrysanthemi, a processive enzyme that catalyzes the hydrolysis of methylester groups from the galacturonic acid residues of homogalacturonan chains, the major component of pectin. Extensive molecular dynamics simulations of this PME in complex with decameric homogalacturonan chains possessing different degrees and patterns of methylesterification show how the carbohydrate substitution pattern governs the dynamics of the substrate in the enzyme's binding cleft, such that substrate dynamics represent a key prerequisite for the PME biological activity. The analyses reveal that correlated rotations around glycosidic bonds of monosaccharide subunits at and immediately adjacent to the active site are a necessary step to ensure substrate processing. Moreover, only substrates with the optimal methylesterification pattern attain the correct dynamical behavior to facilitate processive catalysis. This investigation is one of the few reported examples of a process where the dynamics of a substrate are vitally important.
journal_name
Biophys Jjournal_title
Biophysical journalauthors
Mercadante D,Melton LD,Jameson GB,Williams MA,De Simone Adoi
10.1016/j.bpj.2013.02.049subject
Has Abstractpub_date
2013-04-16 00:00:00pages
1731-9issue
8eissn
0006-3495issn
1542-0086pii
S0006-3495(13)00278-6journal_volume
104pub_type
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