Chapter 1 The Mechanism of Cyclization in Chromophore Maturation of Wild-Type Green Fluorescent Protein Studied with Cluster Model 1.1 Introduction 1.2 Computational Details and Models 1.3 Results and Discussion 1.4 Conclusion Chapter 2 ONIOM(DFT:MM) Investigation of the Mechanism of Cyclization in Chromophore Maturation of Wild-Type Green Fluorescent Protein 2.1 Introduction 2.2 Computational Methods 2.3 Results and Discussion 2.4 Conclusion Chapter 3 New Insights on the Mechanism of Cyclization in Chromophore Maturation of Wild-Type Green Fluorescent Protein 3.1 Introduction 3.2 Computational Methods 3.3 Results and Discussion 3.4 Conclusion Chapter 4 The Effect of S65T on the Cyclization Mechanism of Chromophore in Green Fluorescent Protein 4.1 Introduction 4.2 Computational Details and Models 4.3 Results and Discussion 4.4 Conclusion Chapter 5 The Mechanism of Oxidation in Chromophore Maturation of Wild-Type Green Fluorescent Protein 5.1 Introduction 5.2 Computational Details 5.3 Results and Discussion 5.4 Conclusion Chapter 6 The Mechanism of Dehydration in Chromophore Maturation of Wild-Type Green Fluorescent Protein Studied with Cluster Model 6.1 Introduction 6.2 Computational Methods 6.3 Results and Discussion 6.4 Conclusion Chapter 7 The Mechanism of Dehydration in Chromophore Maturation of Wild-type Green Fluorescent Protein:A QM/MM Study 7.1 Introduction 7.2 Computational Methods 7.3 Results and Discussion 7.4 Conclusion Chapter 8 The Photoswitching Mechanism in the Fluorescent Protein Dreiklang 8.1 Introduction 8.2 Computational Methods and Protocols 8.3 Results and Discussion 8.4 Conclusion References