Protein structure in the truncated (2/2) hemoglobin family.
Protein structure in the truncated (2/2) hemoglobin family.
复制标题
截短 (2/2) 血红蛋白家族的蛋白质结构。
DOI：
10.1080/15216540701225933
复制
发表时间：
2007
期刊：
影响因子：
4.6
通讯作者：
Bolognesi,Martino
中科院分区：
文献类型：
--
作者：
Pesce,Alessandra;Nardini,Marco;Milani,Mario;Bolognesi,Martino
The discovery of protein sequences belonging to the widespread 'truncated hemoglobin' family has been followed in the last few years by extensive analyses of their three‐dimensional structures. Truncated hemoglobins can be classified in three main groups, in light of their overall structural properties. The three groups adopt a 2‐on‐2 α‐helical sandwich fold, based on four main α‐helices of the classical 3‐on‐3 α‐helical sandwich found in vertebrate and invertebrate globins. Each of the three groups displays sequence and structure specific features. Among these, a protein matrix tunnel system is typical of group I, a Trp residue at the G8 topological site is conserved in groups II and III, and residue TyrB10 is almost invariant in the three groups. Despite sequence variability in the heme distal site region, a strongly intertwined, but varied, network of hydrogen bonds stabilizes the heme ligand in the three protein groups. Fine mechanisms of ligand recognition and stabilization may vary based on group‐specific distal site residues and on differing ligand diffusion pathways to the heme. Taken together, the structural considerations here presented underline that 'truncated hemoglobins' result from careful editing of the 3‐on‐3 α‐helical globin sandwich fold, rather than from simple 'truncation' events. Thus, '2/2Hb' appears the most proper term to concisely address this protein family.
