Multiple strategies for O2 transport: from simplicity to complexity

Abstract

SummaryO 2 carriers (extracellular and intracellular as well as monomeric and multimeric) have evolved over the last billion of years, displaying iron and copper reactive centers; very different O 2 carriers may coexist in the same organism. Circulating O 2 carriers, faced to the external environment, are responsible for maintaining an adequate delivery of O 2 to tissues and organs almost independently of the environmental O 2 partial pressure. Then, intracellular globins facilitate O 2 transfer to mitochondria sustaining cellular respiration. Here, molecular aspects of multiple strategies evolved for O 2 transport and delivery are examined, from the simplest myoglobin to the most complex giant O 2 carriers and the red blood cell, mostly focusing on the aspects which have been mainly addressed by the so called 'Rome Group'.

Genetic Loci Implicated in Erythroid Differentiation and Cell Cycle Regulation Are Associated With Red Blood Cell Traits

“…1 The RBC membrane and metabolic machinery facilitate oxygen transport and delivery function of HGB. Disorders involving RBCs, such as anemia, are common and associated with adverse health outcomes, including cardiovascular events.…”

Peroxynitrite scavenging by ferryl sperm whale myoglobin and human hemoglobin

“…In fact, sperm whale Mb, horse heart Mb, and human Hb display the classical histidyl-based heme-distal pocket; the ligand entry to and exit from the heme-distal site occurs via the so-called 'E7-gate' [38][39][40]. On the other hand, the heme-distal region of M. leprae trHbO is completely different, indeed the HisE7 residue present in sperm whale Mb and human Hb chains is replaced by Ala [15,41].…”

CO metabolism, sensing, and signaling

“…In both prokaryotes and eukaryotes, the major molecular targets of CO are heme-proteins [12,13], which display diverse biological functions including sensing and transportation of diatomic gases, catalysis, and electron transfer [11,[13][14][15]. A number of signaling effects of CO depend on the modulation of soluble guanylate cyclase (sGC) and/or activation of mitogen-activated protein kinases (MAPKs).…”