Conserved proline residues prevent dimerization and aggregation in the β‐lactamase BlaC

Protein Science, vol. 33, pp. e4972

Abstract

Evolution leads to conservation of amino acid residues in protein families. Conserved proline residues are usually considered to ensure the correct folding and to stabilize the three-dimensional structure. Surprisingly, proline residues that are highly conserved in class A β-lactamases were found to tolerate various substitutions without large losses in enzyme activity. We investigated the roles of three conserved prolines at positions 107, 226, and 258 in the β-lactamase BlaC from Mycobacterium tuberculosis and found that mutations can lead to dimerization of the enzyme and an overall less stable protein that is prone to aggregate over time. For the variant Pro107Thr, the crystal structure shows dimer formation resembling domain swapping. It is concluded that the proline substitutions loosen the structure, enhancing multimerization. Even though the enzyme does not lose its properties without the conserved proline residues, the prolines ensure the long-term structural integrity of the enzyme.

Authors 8

1. Aleksandra Chikunova Aachen

   Leiden University

   Affiliation as printed

   Leiden Institute of Chemistry Leiden University Leiden The Netherlands

   Leiden Institute of Chemistry, Leiden University, Leiden, The Netherlands

2. Max P. Manley Aachen

   Leiden University

   Affiliation as printed

   Leiden Institute of Chemistry Leiden University Leiden The Netherlands

   Leiden Institute of Chemistry, Leiden University, Leiden, The Netherlands

3. C. N. Heijjer Aachen

   Leiden University

   Affiliation as printed

   Leiden Institute of Chemistry Leiden University Leiden The Netherlands

   Leiden Institute of Chemistry, Leiden University, Leiden, The Netherlands

4. C. S. Drenth Aachen

   Leiden University

   Affiliation as printed

   Leiden Institute of Chemistry Leiden University Leiden The Netherlands

   Leiden Institute of Chemistry, Leiden University, Leiden, The Netherlands

5. Anneloes Cramer‐Blok Aachen

   Leiden University

   Affiliation as printed

   Leiden Institute of Chemistry Leiden University Leiden The Netherlands

   Leiden Institute of Chemistry, Leiden University, Leiden, The Netherlands

6. Misbha Ud Din Ahmad

   The Netherlands Cancer Institute

   Affiliation as printed

   Division of Biochemistry The Netherlands Cancer Institute Amsterdam The Netherlands

   Oncode Institute, Division of Biochemistry The Netherlands Cancer Institute Amsterdam The Netherlands

   Division of Biochemistry, The Netherlands Cancer Institute, Amsterdam, The Netherlands

   Oncode Institute, Division of Biochemistry, The Netherlands Cancer Institute, Amsterdam, The Netherlands

7. Anastassis Perrakis

   The Netherlands Cancer Institute

   Affiliation as printed

   Division of Biochemistry The Netherlands Cancer Institute Amsterdam The Netherlands

   Oncode Institute, Division of Biochemistry The Netherlands Cancer Institute Amsterdam The Netherlands

   Division of Biochemistry, The Netherlands Cancer Institute, Amsterdam, The Netherlands

   Oncode Institute, Division of Biochemistry, The Netherlands Cancer Institute, Amsterdam, The Netherlands

8. Marcellus Ubbink corresponding Aachen

   Leiden University · Imperial College London

   Affiliation as printed

   Leiden Institute of Chemistry Leiden University Leiden The Netherlands

   Department of Infectious Diseases, Imperial College, London, UK

   Leiden Institute of Chemistry, Leiden University, Leiden, The Netherlands

   ZoBio BV, Leiden, The Netherlands

   Zocdoc, New York City, New York, USA