Hugo Lebrette


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Works at Department of Biochemistry and Biophysics
Telephone 08-16 27 46
Visiting address Svante Arrhenius väg 16
Room A 471
Postal address Institutionen för biokemi och biofysik 106 91 Stockholm


Research group: Martin Högbom


A selection from Stockholm University publication database
  • 2018. Vivek Srinivas (et al.). Nature 563, 416-420

    Ribonucleotide reductase (RNR) catalyses the only known de novo pathway for the production of all four deoxyribonucleotides that are required for DNA synthesis1,2. It is essential for all organisms that use DNA as their genetic material and is a current drug target3,4. Since the discovery that iron is required for function in the aerobic, class I RNR found in all eukaryotes and many bacteria, a dinuclear metal site has been viewed as necessary to generate and stabilize the catalytic radical that is essential for RNR activity5,6,7. Here we describe a group of RNR proteins in Mollicutes—including Mycoplasma pathogens—that possess a metal-independent stable radical residing on a modified tyrosyl residue. Structural, biochemical and spectroscopic characterization reveal a stable 3,4-dihydroxyphenylalanine (DOPA) radical species that directly supports ribonucleotide reduction in vitro and in vivo. This observation overturns the presumed requirement for a dinuclear metal site in aerobic ribonucleotide reductase. The metal-independent radical requires new mechanisms for radical generation and stabilization, processes that are targeted by RNR inhibitors. It is possible that this RNR variant provides an advantage under metal starvation induced by the immune system. Organisms that encode this type of RNR—some of which are developing resistance to antibiotics—are involved in diseases of the respiratory, urinary and genital tracts. Further characterization of this RNR family and its mechanism of cofactor generation will provide insight into new enzymatic chemistry and be of value in devising strategies to combat the pathogens that utilize it. We propose that this RNR subclass is denoted class Ie.

  • 2018. Hongyi Xu (et al.). Structure 26 (4), 667-675

    Recent developments of novel electron diffraction techniques have shown to be powerful for determination of atomic resolution structures from micronand nano-sized crystals, too small to be studied by single-crystal X-ray diffraction. In this work, the structure of a rare lysozyme polymorph is solved and refined using continuous rotation MicroED data and standard X-ray crystallographic software. Data collection was performed on a standard 200 kV transmission electron microscope (TEM) using a highly sensitive detector with a short readout time. The data collection is fast (similar to 3 min per crystal), allowing multiple datasets to be rapidly collected from a large number of crystals. We show that merging data from 33 crystals significantly improves not only the data completeness, overall I/sigma and the data redundancy, but also the quality of the final atomic model. This is extremely useful for electron beam-sensitive crystals of low symmetry or with a preferred orientation on the TEM grid.

  • 2017. Franklin D. Fuller (et al.). Nature Methods 14 (4), 443-449

    X-ray crystallography at X-ray free-electron laser sources is a powerful method for studying macromolecules at biologically relevant temperatures. Moreover, when combined with complementary techniques like X-ray emission spectroscopy, both global structures and chemical properties of metalloenzymes can be obtained concurrently, providing insights into the interplay between the protein structure and dynamics and the chemistry at an active site. The implementation of such a multimodal approach can be compromised by conflicting requirements to optimize each individual method. In particular, the method used for sample delivery greatly affects the data quality. We present here a robust way of delivering controlled sample amounts on demand using acoustic droplet ejection coupled with a conveyor belt drive that is optimized for crystallography and spectroscopy measurements of photochemical and chemical reactions over a wide range of time scales. Studies with photosystem IIII, the phytochrome photoreceptor, and ribonucleotide reductase R2 illustrate the power and versatility of this method.

Show all publications by Hugo Lebrette at Stockholm University

Last updated: July 2, 2019

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