Elucidation of a Thermodynamical Feature Attributed to Substrate Binding to the Prokaryotic H+/Oligopeptide Cotransporter YdgR with Calorimetric Analysis : The Substrate Binding Driven by the Change in Entropy Implies the Release of Bound Water Molecules from the Binding Pocket

Here, we have elucidated the substrate recognition mechanism by a prokaryotic H+/oligopeptide cotransporter, YdgR, using isothermal titration calorimetry. Under acidic conditions (pH 6.0), the binding of a dipeptide, Val-Ala, to YdgR elicited endothermic enthalpy, which compensated for the increase in entropy due to dipeptide binding. A series of dipeptides were used in the binding titration. The dipeptides represent Val-X and X-Val, where X is Ala, Ser, Val, Tyr, or Phe. Most dipeptides revealed endothermic enthalpy, which was completely compensated by the increase in entropy due to dipeptide binding. The change in enthalpy due to binding correlated well with the change in entropy, whereas the Gibbs free energy involved in the binding of the dipeptide to YdgR remained unchanged irrespective of dipeptide sequences, implying that the binding reaction was driven by entropy, that is, the release of bound water molecules in the binding pocket. It is also important to clarify that, based on the prediction of water molecules in the ligand-binding pocket of YdgR, the release of three bound water molecules in the putative substrate binding pocket occurred through binding to YdgR. In the comparison of Val-X and X-Val dipeptides, the N-terminal region of the binding pocket might contain more bound water molecules than the C-terminal region. In light of these findings, we suggest that bound water molecules might play an important role in substrate recognition and binding by YdgR.

Medienart:

E-Artikel

Erscheinungsjahr:

2023

Erschienen:

2023

Enthalten in:

Zur Gesamtaufnahme - volume:62

Enthalten in:

Biochemistry - 62(2023), 11 vom: 06. Juni, Seite 1608-1618

Sprache:

Englisch

Beteiligte Personen:

Omori, Akiko [VerfasserIn]
Sasaki, Shotaro [VerfasserIn]
Kikukawa, Takashi [VerfasserIn]
Shimono, Kazumi [VerfasserIn]
Miyauchi, Seiji [VerfasserIn]

Links:

Volltext

Themen:

059QF0KO0R
Dipeptides
Journal Article
Oligopeptides
Research Support, Non-U.S. Gov't
Symporters
Water

Anmerkungen:

Date Completed 07.06.2023

Date Revised 09.06.2023

published: Print-Electronic

Citation Status MEDLINE

doi:

10.1021/acs.biochem.2c00673

funding:

Förderinstitution / Projekttitel:

PPN (Katalog-ID):

NLM356665887