AQA · A-Level · Chemistry
Course version: 7405 · Version from Sept 2016
Enzymes (A-level only): Computers can be used to help design such drugs.
Designing an inhibitor by trial and error means synthesising and testing thousands of compounds, which is slow and expensive.
Checked against the AQA 7405 specification (opens in a new tab) on .
- Point 4 of 5
- 4 key terms
Study notes
From the checked teaching notes for this specification point.
The idea
Designing an inhibitor by trial and error means synthesising and testing thousands of compounds, which is slow and expensive. Computer modelling shortens the search. The three-dimensional structure of the enzyme is first determined, usually by X-ray crystallography, and software then maps the active site: its shape, the positions of the charged and polar groups and the places where hydrogen bonds could form. Candidate molecules are docked into that model on screen and scored for how well they fit and how strongly they would bind, so only the most promising few are actually made and tested in the laboratory. The model must be built for the correct enantiomer, since only one hand of the molecule will fit.
What earns the marks
- The model being built from the known three-dimensional structure of the enzyme's active site.
- Candidate molecules being tested for fit on the computer before they are synthesised.
- Naming an interaction the model predicts, such as hydrogen bonding to groups in the site.
- The benefit, that fewer compounds have to be made and tested so cost and time fall.
Common mistakes and how to put them right
Saying the computer manufactures the drug.
Claiming computer design removes the need for laboratory and clinical testing.
Ignoring that only one enantiomer of the candidate will fit the site.
Describing the model as predicting the percentage yield of the synthesis.
Exam tips
- Frame the answer around the active site: the computer models the site, then tests molecules against it.
- A benefit mark needs a comparison, so say 'fewer compounds need to be synthesised' rather than 'it is better'.
Try the lesson
The start of the Enzymes (A-level only): Computers can be used to help design such drugs. lesson, made from checked teaching notes for this specification point.
Have a go first
Computers can be used to help design drugs that block an enzyme's active site. What is the main advantage of using a computer for this purpose?
Listen
Designing an inhibitor by trial and error means synthesising and testing thousands of compounds, which is slow and expensive. Computer modelling shortens the search. The three-dimensional structure of the enzyme is first determined, usually by X-ray crystallography, and software then maps the active site: its shape, the positions of the charged and polar groups and the places where hydrogen bonds could form. Candidate molecules are docked into that model on screen and scored for how well they fit and how strongly they would bind, so only the most promising few are actually made and tested in the laboratory. The model must be built for the correct enantiomer, since only one hand of the molecule will fit. A strong answer earns marks for these points. the model being built from the known three-dimensional structure of the enzyme's active site. candidate molecules being tested for fit on the computer before they are synthesised. naming an interaction the model predicts, such as hydrogen bonding to groups in the site. the benefit, that fewer compounds have to be made and tested so cost and time fall. Exam tip: Frame the answer around the active site: the computer models the site, then tests molecules against it.
Key words
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computer modelling
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structure of the active site
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molecular docking
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reduced cost of development
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See every definition
- computer modelling
- Using computers to shorten the search when designing an inhibitor, instead of synthesising and testing thousands of compounds by trial and error.
- structure of the active site
- Mapped by software after the three-dimensional structure of the enzyme is determined, covering its shape, the positions of charged and polar groups and where hydrogen bonds could form.
- molecular docking
- Candidate molecules are docked into the model on screen and scored for how well they fit and how strongly they would bind.
- reduced cost of development
- Fewer compounds have to be made and tested, so cost and time fall.
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