| Autor: |
Hemmann JL; Institute of Microbiology, Eidgenössische Technische Hochschule Zurich, 8093 Zurich, Switzerland., Wagner T; Max Planck Institute for Terrestrial Microbiology, 35043 Marburg, Germany.; Max Planck Institute for Marine Microbiology, 28359 Bremen, Germany., Shima S; Max Planck Institute for Terrestrial Microbiology, 35043 Marburg, Germany., Vorholt JA; Institute of Microbiology, Eidgenössische Technische Hochschule Zurich, 8093 Zurich, Switzerland; jvorholt@ethz.ch. |
| Jazyk: |
angličtina |
| Zdroj: |
Proceedings of the National Academy of Sciences of the United States of America [Proc Natl Acad Sci U S A] 2019 Dec 17; Vol. 116 (51), pp. 25583-25590. Date of Electronic Publication: 2019 Nov 27. |
| DOI: |
10.1073/pnas.1911595116 |
| Abstrakt: |
Methylotrophy, the ability of microorganisms to grow on reduced one-carbon substrates such as methane or methanol, is a feature of various bacterial species. The prevailing oxidation pathway depends on tetrahydromethanopterin (H 4 MPT) and methylofuran (MYFR), an analog of methanofuran from methanogenic archaea. Formyltransferase/hydrolase complex (Fhc) generates formate from formyl-H 4 MPT in two consecutive reactions where MYFR acts as a carrier of one-carbon units. Recently, we chemically characterized MYFR from the model methylotroph Methylorubrum extorquens and identified an unusually long polyglutamate side chain of up to 24 glutamates. Here, we report on the crystal structure of Fhc to investigate the function of the polyglutamate side chain in MYFR and the relatedness of the enzyme complex with the orthologous enzymes in archaea. We identified MYFR as a prosthetic group that is tightly, but noncovalently, bound to Fhc. Surprisingly, the structure of Fhc together with MYFR revealed that the polyglutamate side chain of MYFR is branched and contains glutamates with amide bonds at both their α- and γ-carboxyl groups. This negatively charged and branched polyglutamate side chain interacts with a cluster of conserved positively charged residues of Fhc, allowing for strong interactions. The MYFR binding site is located equidistantly from the active site of the formyltransferase (FhcD) and metallo-hydrolase (FhcA). The polyglutamate serves therefore an additional function as a swinging linker to shuttle the one-carbon carrying amine between the two active sites, thereby likely increasing overall catalysis while decreasing the need for high intracellular MYFR concentrations.
Competing Interests: The authors declare no competing interest.
(Copyright © 2019 the Author(s). Published by PNAS.) |
| Databáze: |
MEDLINE |
| Externí odkaz: |
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