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: ["Protein", "Chemical"].

Please return the output as a JSON object of the format: {"Chemical" : ["Dexamethasone", ...], "Protein" : ["BRCA-1", ...]}. 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 Structural Snapshot of Cytochrome P450 2B4 in Complex with Paroxetine Provides Insights into Ligand Binding and Clusters of Conformational States.
An X-ray crystal structure of cytochrome P450 2B4 in complex with the drug paroxetine was solved at 2.14 Å resolution. The structure revealed a conformation intermediate to that of the recently solved complex with amlodipine and of the more compact complex with 4-(4-chlorophenyl)imidazole in terms of the placement of the F-G cassette. Moreover, the comparison of the new structure with 15 previously solved structures of P450 2B4 revealed some new insights into determinants of active site size and shape. The 2B4-paroxetine structure is nearly superimposable on a previously solved closed structure in a ligand free state. Despite the overall conformational similarity among multiple closed structures, the active site cavity volume of the paroxetine complex is enlarged. Further analysis of the accessible space and binding pocket near the heme reveals a new sub-chamber that resulted from the movement of secondary structural elements and rearrangements of active site side chains. Overall, the results from the comparison of all the 16 structures of P450 2B4 demonstrate a cluster of protein conformations that were observed in the presence or absence of various ligands.
{"Chemical": ["paroxetine", "4-(4-chlorophenyl)imidazole", "amlodipine", "Paroxetine"], "Protein": ["Cytochrome P450 2B4", "P450 2B4", "cytochrome P450 2B4", "2B4"]}