Half sphere exposure Half sphere exposure Half Sphere Exposure (HSE) is a protein solvent exposure measure that was first introduced by . Like all solvent exposure measures it measures how buried amino acid residues are in a protein. It is found by counting the number of amino acid neighbors within two half spheres of chosen radius around the amino acid. The calculation of HSE is found by dividing a contact number (CN) sphere in two halves by the plane perpendicular to the Cβ-Cα vector. This simple division of the CN sphere results in two strikingly different measures, HSE-up and HSE-down. HSE-up is defined
Inversion in a sphere in this article are dependent on three simple ideas: (See fig 1) (See fig 2) (See fig 3) Note 4: Generally, the inverse of a line is a circle through the centre of reference. Note 5: Generally, the inverse of a plane is a sphere through the centre of reference. (See fig 4) (See fig 5) Note 6: Generally the inverse of a sphere is a sphere (Cf Figs 3, 4, 5) Note 7: Generally the inverse of a circle is a circle. Inversion in a sphere In geometry, inversion in a sphere is a transformation of Euclidean space that