Non-functional conserved residues in globins and their possible role as a folding nucleus.

摘要: Abstract Structure-based sequence alignment of 728 sequences different globin subfamilies shows that in each subfamily there are two clusters consensually conserved residues. The first is the well-known “functional” cluster which includes six heme-binding residues (Phe CD1, His F8; aliphatic E11, FG5; hydrophobic F4, G5) and seven other (Pro C2; H19; B10, B13, B14, CD4, E4) do not bind heme but belong to its immediate neighborhood. second revealed here (aliphatic A8, G16, G12; aromatic A12; H8 possibly H12) distant from heme. It entirely non-polar one turn ( i , + 4 positions) helices A, G, H. known H formed at earliest stage apomyoglobin folding remain relatively stable equilibrium molten globule state, likely be tightly packed with this state. We have shown existence similar c -type cytochromes, distal -cytochromes N C-terminal α-helices. These cytochrome protein folding, observed behavior globins. At least these large families cytochromes globins) a close similarity mutual positions non-functional assume requisite for fast correct both into their 3D structures.