Bioinformatics Project from Scratch - Drug Discovery Part 5 (Compare Models)
**Part 1: Calculating Lapinski Descriptors**
In this part of the episode, we're going to discuss how you can calculate Lapinski descriptors used for evaluating the likelihood of being a drug-like molecule. These descriptors are an essential tool in chemoinformatics and provide valuable insights into the properties of molecules. To begin with, it's essential to understand what Lapinski descriptors are and how they were developed. The Lapinski descriptors were introduced by Zbigniew Lapinski, a Polish-American biochemist who worked at the University of Illinois at Urbana-Champaign.
The Lapinski descriptors are based on the concept of "descriptors" in chemoinformatics, which refer to numerical values that can be calculated from molecular structures. These descriptors are used to describe the properties of molecules and can be used to predict their potential biological activity. The Lapinski descriptors were developed using a combination of machine learning algorithms and chemical intuition.
To calculate the Lapinski descriptors, we need access to a dataset of compounds with known biological activities. This dataset is typically provided by researchers in the field of chemoinformatics. Once you have this dataset, you can use software packages such as Paddle to calculate the Lapinski descriptors. Paddle is a popular open-source software package for calculating molecular descriptors.
After obtaining the Lapinski descriptors, we can perform some basic exploratory data analysis (EDA) on these descriptors. EDA involves visualizing and summarizing the distribution of the descriptors in order to gain insights into their properties and behavior. This can be done using simple box plots and scatter plots.
**Part 2: Exploratory Data Analysis**
In this part of the episode, we're going to discuss how you can perform exploratory data analysis (EDA) on the Lapinski descriptors. EDA is an essential step in chemoinformatics, as it allows us to understand the properties and behavior of molecular descriptors.
To begin with, we need to visualize the distribution of the Lapinski descriptors using box plots and scatter plots. These visualizations can help us identify patterns and trends in the data that might not be immediately apparent from a summary of the mean and standard deviation values.
Box plots are particularly useful for visualizing the distribution of multiple variables, as they provide a sense of central tendency and variability. By plotting the box plots side by side, we can compare the distributions of different Lapinski descriptors to identify similarities and differences between them.
Scatter plots, on the other hand, are used to visualize the relationship between two variables at a time. These plots can help us understand how changes in one variable affect another variable. For example, we might plot the Lapinski descriptor "hydrophobicity" against the molecular weight of the compound.
By analyzing the distribution and relationships between the Lapinski descriptors, we can gain insights into their properties and behavior that will be useful for downstream analysis and modeling tasks. This includes identifying outliers and extreme values, as well as understanding how different descriptors interact with each other.
**Part 3: Target Protein and Machine Learning**
In this part of the episode, we're going to discuss how you can use machine learning algorithms to predict biological activity based on molecular properties. We'll be using the Acetylcholine Esterase (AChE) protein as our target protein, which provides a larger dataset for modeling compared to some other proteins.
To begin with, we need to calculate the molecular descriptors of the compounds in our dataset using software packages such as Paddle. These descriptors provide valuable information about the properties and behavior of the molecules, including their hydrophobicity, polar surface area, and logD values.
Once we have calculated the molecular descriptors, we can split our dataset into training and testing sets using a 80:20 ratio. This is essential for evaluating the performance of machine learning models, as it allows us to assess how well they generalize to unseen data.
Next, we'll use the pandas library to load the datasets and assign them to x and y variables. We'll also use the seaborn library to visualize the distribution of our molecular descriptors and understand their properties better.
**Part 4: Machine Learning Comparison**
In this part of the episode, we're going to compare several machine learning algorithms using the Lazy Predict library to predict biological activity based on molecular properties. The goal is to determine which algorithm performs best in predicting the biological activity of compounds with different molecular structures.
To begin with, we'll import the necessary libraries and load our dataset into x and y variables. We'll also split our dataset into training and testing sets using a 80:20 ratio.
Next, we'll use the Lazy Predict library to build models based on each of the machine learning algorithms available in the library. This includes Random Forest, Gradient Boosting, LightGBM, and XGBoost.
For each model, we'll evaluate its performance using metrics such as R-squared values and RMSE. We'll also calculate the training time for each model to understand how computationally intensive they are.
Finally, we'll visualize our results using bar plots and scatter plots to compare the performance of different machine learning algorithms. By comparing these results, we can determine which algorithm performs best in predicting biological activity based on molecular properties.
By completing this episode, you should now have a good understanding of how to calculate Lapinski descriptors, perform exploratory data analysis, use machine learning algorithms to predict biological activity, and compare the performance of different models using Lazy Predict.