You will be shown an abstract from a biomedical research paper. Given this abstract, your task is to extract all unique entities of the following types: ["Chemical"].

Please return the output as a JSON object of the format: {"Chemical": ["Arsenic", ...]}. The keys should be entity types and values should be lists of extracted entities belonging to the corresponding type. If you cannot find entities belonging to a specific type, the value should be [].

Only output the JSON object and do not include any additional text.

Abstract:

A Novel Automethylation Reaction in the Aspergillus nidulans LaeA Protein Generates S-Methylmethionine. The filamentous fungi in the genus Aspergillus are opportunistic plant and animal pathogens that can adapt to their environment by producing various secondary metabolites including lovastatin, penicillin, and aflatoxin. The synthesis of these small molecules is dependent on gene clusters that are globally regulated by the LaeA protein. Null mutants of LaeA in all pathogenic fungi examined to date show decreased virulence coupled with reduced secondary metabolism. Although the amino acid sequence of LaeA contains the motifs characteristic of seven-beta-strand methyltransferases, a methyl-accepting substrate of LaeA has not been identified. In this work, we did not find a methyl-accepting substrate in A. nidulans with various assays including in vivo S-adenosyl-[methyl-(3)H]methionine labeling, targeted in vitro methylation experiments using putative protein substrates, or in vitro methylation assays using whole cell extracts grown under different conditions. However, in each experiment LaeA was shown to self-methylate. Amino acid hydrolysis of radioactively-labeled LaeA followed by cation exchange and reverse phase chromatography identified methionine as the modified residue. Point mutations show that the major site of modification of LaeA is on methionine-207. However, in vivo complementation showed that methionine-207 is not required for the biological function of LaeA. LaeA is the first protein to exhibit automethylation at a methionine residue. These findings not only indicate LaeA may perform novel chemistry with S-adenosylmethionine, but also provide new insights into the physiological function of LaeA.
{"Chemical": ["S-adenosyl-[methyl-(3)H]methionine", "penicillin", "amino acid", "aflatoxin", "S-adenosylmethionine", "Amino acid", "methionine", "S-Methylmethionine", "methyl", "lovastatin"]}