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Biochim Biophys Acta. 2016 Jun;1860(6):1343-53. doi: 10.1016/j.bbagen.2016.03.027. Epub 2016 Mar 23.

Heme interacts with histidine- and tyrosine-based protein motifs and inhibits enzymatic activity of chloramphenicol acetyltransferase from Escherichia coli.

Author information

1
Pharmaceutical Chemistry I, Institute of Pharmacy, University of Bonn, 53119 Bonn, Germany.
2
Leibniz Institute on Aging, Fritz Lipmann Institute, 07745 Jena, Germany.
3
Institute of Physical and Theoretical Chemistry, University of Bonn, 53115 Bonn, Germany.
4
Center for Sepsis Control and Care (CSCC), Jena University Hospital, 07747 Jena, Germany; Leibniz Institute of Photonic Technology, 07745 Jena, Germany.
5
Centre National de la Recherche Scientifique (CNRS), Bioénergetique et Ingenierie des Protéines, UMR 7281, 13009 Marseille, France.
6
Center for Sepsis Control and Care (CSCC), Jena University Hospital, 07747 Jena, Germany; Leibniz Institute of Photonic Technology, 07745 Jena, Germany; Institute of Physical Chemistry and Abbe Center of Photonics, Friedrich Schiller University Jena, 07743 Jena, Germany.
7
Leibniz Institute on Aging, Fritz Lipmann Institute, 07745 Jena, Germany. Electronic address: oliver.ohlenschlaeger@leibniz-fli.de.
8
Pharmaceutical Chemistry I, Institute of Pharmacy, University of Bonn, 53119 Bonn, Germany. Electronic address: dimhof@uni-bonn.de.

Abstract

BACKGROUND:

The occurrence of free organismal heme can either contribute to serious diseases or beneficially regulate important physiological processes. Research on transient binding to heme-regulatory motifs (HRMs) in proteins resulted in the discovery of numerous Cys-based, especially Cys-Pro (CP)-based motifs. However, the number of His- and Tyr-based protein representatives is comparatively low so far, which is in part caused by a lack of information regarding recognition and binding requirements.

METHODS:

To understand transient heme association with such motifs on the molecular level, we analyzed a set of 44 His- and Tyr-based peptides using UV-vis, resonance Raman, cw-EPR and 2D NMR spectroscopy.

RESULTS:

We observed similarities with Cys-based sequences with respect to their spectral behavior and complex geometries. However, significant differences regarding heme-binding affinities and sequence requirements were also found. Compared to Cys-based peptides and proteins all sequences investigated structurally display increased flexibility already in the free-state, which is also maintained upon heme association. The acquired knowledge allowed for identification and prediction of a His-based HRM in chloramphenicol acetyltransferase from Escherichia coli as potential heme-regulated protein. The enzyme's heme-interacting capability was studied, and revealed an inhibitory effect of heme on the protein activity with an IC50 value of 57.69±4.37 μM.

CONCLUSIONS:

It was found that heme inhibits a bacterial protein carrying a potential His-based HRM. This finding brings microbial proteins more into focus of regulation by free heme.

GENERAL SIGNIFICANCE:

Understanding transient binding and regulatory action of heme with bacterial proteins, being crucial for survival, might promote new strategies for the treatment of bacterial infections.

KEYWORDS:

Chloramphenicol acetyltransferase; Heme-peptide/protein complex; Heme-regulatory motif (HRM); Histidine-based HRM; Tyrosine-based HRM

PMID:
27015758
DOI:
10.1016/j.bbagen.2016.03.027
[Indexed for MEDLINE]

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