Medical Genetics a nucleosome consists of approximately 1.8 turns of dNA wound around a core particle of histone proteins. The core particle is a roughly heart-shaped octamer of 4 types of histones: two each of the H2A, H2B, H3, and H4 proteinsMedical Genetics A nucleosome consists of approximately 1.8 turns of DNA wound around a core particle of histone proteins. The core particle is a roughly heart-shaped octamer of 4 types of histones: two each of the H2A, H2B, H3, and H4 proteins