Volume 9, Issue 6 p. 1572-1583

A novel Dps-type protein from insect gut bacteria catalyses hydrolysis and synthesis of N-acyl amino acids

Liyan Ping

Liyan Ping

Department of Bioorganic Chemistry, Max Planck Institute for Chemical Ecology, Hans-Knöll-Str. 8, 07745 Jena, Germany.

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Rita Büchler

Rita Büchler

Department of Bioorganic Chemistry, Max Planck Institute for Chemical Ecology, Hans-Knöll-Str. 8, 07745 Jena, Germany.

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Axel Mithöfer

Axel Mithöfer

Department of Bioorganic Chemistry, Max Planck Institute for Chemical Ecology, Hans-Knöll-Str. 8, 07745 Jena, Germany.

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Aleš Svatoš

Aleš Svatoš

Department of Bioorganic Chemistry, Max Planck Institute for Chemical Ecology, Hans-Knöll-Str. 8, 07745 Jena, Germany.

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Dieter Spiteller

Dieter Spiteller

Department of Bioorganic Chemistry, Max Planck Institute for Chemical Ecology, Hans-Knöll-Str. 8, 07745 Jena, Germany.

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Konrad Dettner

Konrad Dettner

Animal Ecology II, University of Bayreuth, Universitätsstraße 30, 95447 Bayreuth, Germany.

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Sophie Gmeiner

Sophie Gmeiner

Animal Ecology II, University of Bayreuth, Universitätsstraße 30, 95447 Bayreuth, Germany.

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Jörn Piel

Jörn Piel

Kekulé Institute of Organic Chemistry and Biochemistry, University of Bonn, Gerhard-Domagk-Str. 1, 53121 Bonn, Germany.

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Bernhard Schlott

Bernhard Schlott

Department of Biochemistry, Fritz Lipmann Institute, Beutenbergstraße 11, 07745 Jena, Germany.

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Wilhelm Boland

Corresponding Author

Wilhelm Boland

Department of Bioorganic Chemistry, Max Planck Institute for Chemical Ecology, Hans-Knöll-Str. 8, 07745 Jena, Germany.

*E-mail [email protected]; Tel. (+49) 3641 57 1200; Fax (+49) 3641 57 1202.Search for more papers by this author
First published: 02 April 2007
Citations: 40

Summary

A novel type of a microbial N-acyl amino acid hydrolase (AAH) from insect gut bacteria was purified, cloned and functionally characterized. The enzyme was obtained from Microbacterium arborescens SE14 isolated from the foregut of larvae of the generalist herbivore Spodoptera exigua. The substrates of AAH are N-acyl-glutamines previously reported to elicit plant defence reactions after introduction into the leaf during feeding. The isolated AAH catalyses the hydrolysis of the amide bond (Km = 36 μmol l−1) and, less efficient, the formation (Km = 3 mmol l−1) of the elicitor active N-acyl amino acids. The AAH from M. arborescens SE14 shows no homology to known fatty acyl amidases (EC 3.5.1.4) but belongs to the family of Dps proteins (DNA-binding protein from starved cell). In line with other DPS proteins AAH is a homododecamer (monomer 17 181 Da) and contains iron atoms (c. 1–16 iron atoms per subunit). Unlike genuine DPS proteins the enzyme does not significantly bind DNA. Amino acid hydrolase is the first member of the DPS family that catalyses the cleavage or formation of amide bonds. The participation of a microbial enzyme in the homeostasis of N-acyl-glutamines in the insect gut adds further complexity to the interaction between plants and their herbivores.