Question

What changes are seen in the amino acids when hemoglobin changes its state from t state to r state? Explain all tge interactions of the subunits.

Answer 1

a) Oxygen binding causes change from T-state to R state(narrows the binding pocket for BPG, thus preculding BPG binding)

When oxygen is absent T state is more stable and the T state is stabilized by a greater number of ion pairs, which lie at the a1b2 interface the binding of oxygen to hemoglobin triggers change to conformation R .

the ab subunits pairs slide past each other and rotate to narrow the pocket in between beta subunits and in this process the ion pairs that stabilized the T state are His HC3 and amino acids( Asp FG1 Lys C5) and His HC3.

b)The β subunits and the α subunits

Positively charged side chains and chain termini involved in ion pairs and, their negatively charged partners

The Lys C5 of each α subunit and Asp FG1 of each β subunit are visible.. The transition from the T state to the R state shifts the subunit pairs substantially, affecting certain ion pairs. Most noticeably, the His HC3 residues at the carboxyl termini of the β subunits, which are involved in ion pairs in the T state, rotate in the R state toward the center of the molecule, where they are no longer in ion pairs. Another dramatic result of the T¦R transition is a narrowing of the pocket between the β subunits.

Conformational change is triggered by oxygen binding Changes in conformation near heme on O2 binding to deoxyhemoglobin.

The shift in the position of helix F when heme binds O2 is thought to be one of the adjustments that triggers the T → R transition.