User:Tommie Hata/Introduction to Protein Engineering-Subtilisin

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This Protein Engineering module has been developed using material from Dr. Scott Banta's course, Protein Engineering (chemical engineering department at Columbia University).

PDB ID 2sic, Subtilisin BPN


Contents

Introduction

The structure to the right is subtilisin BPN' and streptomyces subtilisin inhibitor (PDB ID: 2sic). The subtilisin enzyme is colored white while the Streptomyces subtilisin inhibitor is colored yellow. By , we can take a closer look at the active site. Enzyme-inhibitor structures are common in the Protein Data Bank (PDB)compared to enzyme-substrate structures. This is because enzyme-substrate complexes are often transient. The inability to form a stable enzyme-substrate complex makes it difficult to grow a crystal for structural determination through X-ray crystallography. In comparison, enzyme inhibitors bind their targets with much higher affinity (low dissociation constant) which makes the enzyme-inhibitor complex more favorable to crystallize for structure determination.

Function

Subtilisin is a serine protease. The is made up of aspartic acid (Asp32), histidine (His64), and serine (Ser221). Subtilisins are the proteases used in many laundry and dishwashing detergents. In 2002 alone, 900 tons of subtilisin was produced and used in the EU. Subtilisin received the first US patent for an engineered protein in 1988.

Engineered features

Subtilisins already possess a very high natural stability, partially because they are extracelluar enzymes optimized to work outside of the cell. Yet there are additional characteristics that have been engineered into industrial subtilisins for turn them into better products.

A calcium-independent thermostable subtilisin BPN mutant (PDB ID: 1gnv)

PDB ID 1gnv, A calcium-independent thermostable subtilisin BPN mutant

PDB ID 2sic, Subtilisin BPN




, which has been minimized in the view to highlight the chain bound in the active site of subtilisin.


Reference

Structures

  • Takeuchi Y, Satow Y, Nakamura KT, Mitsui Y. Refined crystal structure of the complex of subtilisin BPN' and Streptomyces subtilisin inhibitor at 1.8 A resolution. J Mol Biol. 1991 Sep 5;221(1):309-25. PMID:1920411

Features and industrial use

Engineering

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Tommie Hata

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