Studying Protein Interior with Fractal Dimension

Here we look at the interior of protein structures, as viewed through the prism of fractal dimensions. History of application of fractal dimension-based constructs to probe protein interior dates back to the development of theory of fractal dimension itself. Numerous approaches have been tried and tested over a course of 30 years. All of these bring to light some or the other facet of symmetry of self-similarity prevalent in protein interior. Later half of the last decade, especially, has been phenomenal; in terms of the works that innovatively stretched the limits of fractal dimension-based studies to present an array of unexpected results about biophysical properties of protein interior. Here, starting from the fundamental of fractals, we will learn about the commonality (and the lack of it) between various approaches, before exploring the patterns in the results that they have produced. Clustering these approaches in major schools of protein self-similarity studies, we will attempt to describe the evolution of fractal dimension-based methodologies. Then, after attempting to work out the genealogy of approaches (and results), we will learn about certain inherent limitations of fractal constructs. Finally, we will attempt to identify the areas and specific questions where the implementation of fractal dimension-based constructs can be of paramount help to unearth latent information about protein structural properties.

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