Related Experiment Video
Updated: Jul 18, 2026
09:08
From a Natural Product to Its Biosynthetic Gene Cluster: A Demonstration Using Polyketomycin from Streptomyces diastatochromogenes Tü6028
Published on: January 13, 2017
Biphenyl synthase, a novel type III polyketide synthase.
1Institut für Pharmazeutische Biologie, Technische Universität Braunschweig, Mendelssohnstrasse 1, 38106, Braunschweig, Germany.
Planta
|November 17, 2006
Summary
Researchers identified biphenyl synthase (BIS), a novel enzyme crucial for producing antimicrobial compounds in Rosaceae plants. This discovery enhances our understanding of plant defense mechanisms and enzyme evolution.
Area of Science:
- Biochemistry
- Plant Science
- Molecular Biology
Background:
- Biphenyls and dibenzofurans are key phytoalexins in Maloideae (Rosaceae).
- These antimicrobial compounds are synthesized using biphenyl synthase (BIS).
Purpose of the Study:
- To clone and characterize the cDNA encoding biphenyl synthase (BIS) from Sorbus aucuparia.
- To elucidate the enzymatic mechanism and substrate specificity of BIS.
- To understand the evolutionary relationships of BIS within the type III polyketide synthase (PKS) superfamily.
Main Methods:
- Cloning of BIS cDNA from yeast-extract-treated Sorbus aucuparia cell cultures.
- Analysis of amino acid sequence identity with other type III PKSs.
- Enzyme activity assays to determine substrate preferences (benzoyl-CoA vs. 4-coumaroyl-CoA).
- Phylogenetic analysis of BIS and related enzymes.
Main Results:
- BIS was identified as a novel type III PKS with approximately 60% amino acid identity to related enzymes.
- BIS preferentially uses benzoyl-CoA as a starter substrate, leading to 3,5-dihydroxybiphenyl production via aldol condensation.
- BIS does not accept CoA-linked cinnamic acids, unlike chalcone synthase (CHS).
- BIS expression is rapidly and strongly induced by yeast extract, while CHS expression is not.
- Phylogenetic analysis places BIS close to benzophenone synthase (BPS).
Conclusions:
- The molecular characterization of BIS provides insights into the functional diversity of type III PKSs.
- BIS plays a distinct role in phytoalexin biosynthesis compared to CHS.
- Understanding BIS contributes to the study of plant secondary metabolism and enzyme evolution.
Related Concept Videos
01:24Biosynthesis in Bacteria
Biosynthesis in bacteria is a fundamental anabolic process that generates essential macromolecules, including proteins, nucleic acids, lipids, and polysaccharides. These macromolecules are critical for cellular growth, replication, and function. The process is tightly regulated and energetically linked to catabolic pathways to ensure optimal resource utilization.Biosynthetic pathways begin with precursor metabolites such as pyruvate, acetyl-CoA, and glucose-6-phosphate derived from glycolysis,...
01:30Production of Pharmaceuticals
Industrial insulin production uses genetically engineered E. coli expressing a proinsulin gene controlled by a tryptophan promoter and containing a methionine linker for later cleavage. The cells also carry ampicillin resistance for selective growth. Seed cultures are stored at −80 °C and production begins by thawing a small amount to inoculate starter cultures, which are progressively scaled to a 50,000-L bioreactor. In the bioreactor, E. coli grow in nutrient-rich media under sterile, tightly...
01:19Allosteric Proteins-ATCase
Binding sites linkages can regulate a protein's function. For example, enzyme activity is often regulated through a feedback mechanism where the end product of the biochemical process serves as an inhibitor.
Aspartate transcarbamoylase (ATCase) is a cytosolic enzyme that catalyzes the condensation of L-aspartate and carbamoyl phosphate to N-carbamoyl-L-aspartate. This reaction is the first step in pyrimidine biosynthesis. UTP and CTP, the end products of the pyrimidine synthesis pathway,...
Aspartate transcarbamoylase (ATCase) is a cytosolic enzyme that catalyzes the condensation of L-aspartate and carbamoyl phosphate to N-carbamoyl-L-aspartate. This reaction is the first step in pyrimidine biosynthesis. UTP and CTP, the end products of the pyrimidine synthesis pathway,...
01:28Biosynthesis of Nucleic Acids
Nucleic acid biosynthesis is a fundamental biochemical process that produces the purine and pyrimidine nucleotides essential for DNA and RNA synthesis. This pathway maintains a balanced nucleotide pool, preventing imbalances that could jeopardize genetic integrity and cellular function. Given the crucial role of nucleotides, their synthesis is tightly regulated to ensure proper cellular homeostasis.Purine BiosynthesisThe biosynthesis of purine nucleotides begins with ribose-5-phosphate, a...
01:26Thermal and Photochemical Electrocyclic Reactions: Overview
Electrocyclic reactions are reversible reactions. They involve an intramolecular cyclization or ring-opening of a conjugated polyene. Shown below are two examples of electrocyclic reactions. In the first reaction, the formation of the cyclic product is favored. In contrast, in the second reaction, ring-opening is favored due to the high ring strain associated with cyclobutene formation.
01:56Riboswitches
Riboswitches are non-coding mRNA domains that regulate the transcription and translation of downstream genes without the help of proteins. Riboswitches bind directly to a metabolite and can form unique stem-loop or hairpin structures in response to the amount of the metabolite present. They have two distinct regions – a metabolite-binding aptamer and an expression platform.
The aptamer has high specificity for a particular metabolite which allows riboswitches to specifically regulate...
The aptamer has high specificity for a particular metabolite which allows riboswitches to specifically regulate...