A 55 year old male patient complains of abnormal growth on right cheek. Patient has a habit of tobacco chewing since 30 years. Radiologic findings reveal 8x8cm fungating mass, invading maxilla and mandible on right side. Patient was advised palliative chemotherapy with cisplastin. All of the following changes in DNA are caused by this drug EXCEPT-

In general, adenine base containing DNA tracts are rigid and straight. Bent conformation of DNA occurs when A-tracts are replaced by other bases or a collapse of the helix into the minor groove of A-tract. Bending in DNA structure has also been reported due to photochemical damage or mispairing of bases. Certain  antitumor  drugs  (e.g. cisplatin) produce bent structure in  DNA. Such changed structure can take up proteins that damage the DNA. Satyanarayana- Biochemistry, 3rd edition, pg-77