Initial biophysical characterization ofAmynthas gracilisgiant extracellular hemoglobin (HbAg)

Author(s)

Oliveira, J. B. S. ^{[1, 2]} ; Ramos, L. ^{[1, 2]} ; Souza, C. O. ^{[1, 2]} ; Sebastiao, I ^{[1, 2]} ; Caruso, C. ^[2] ; Carvalho, F. A. O. ^[3] ; Carvalho, J. W. P. ^[4] ; Morgante, P. G. ^[2] ; Santiago, P. S. ^[2]

Affiliation

^[1] Sao Paulo State Univ UNESP, Inst Chem, Araraquara, SP - Brazil

^[2] Sao Paulo State Univ Unesp, Campus Registro, Registro, SP - Brazil

^[3] Fed Univ South & Southeast Para Unifesspa, Maraba, PA - Brazil

^[4] Univ Estado Mato Grosso, Barra Do Bugres, MT - Brazil

• Document type: Journal article
• Source: EUROPEAN BIOPHYSICS JOURNAL WITH BIOPHYSICS LETTERS; v. 49, n. 6 AUG 2020.
• Web of Science Citations: 0

Abstract

The aim of the present work was the biophysical characterization of theAmynthas gracilishemoglobin (HbAg). The oxy-HbAg optical absorption data, with Soret and Q bands centered at 415, 540 and 575 nm, were stable and unchanged at pH 7.0. An increase in pH promotes decrease in the intensity in the optical absorption bands, suggesting an oligomeric dissociation and partial oxidation. Identical stability at pH 7.0 was observed in DLS results that presented a hydrodynamic diameter of 28 nm, characteristic of the whole oligomer. DLS shows that HbAg undergoes oligomeric dissociation and an aggregation/denaturation process that corroborates spectroscopic data. Our results showed that the monomerdpresents four isoforms with molecular mass (MM) ranging from 16,244 to 16,855 Da; the trimer subunit presents two isoforms, (abc)(1)and (abc)(2), with MM of 51,415 +/- 20 Da and 51,610 +/- 14 Da, respectively, and a less intense species, at 67,793 Da, assigned to the tetramerabcd. Monomeric chains a, obtained from reduction of the disulfide-bonded trimerabc, present four isoforms with MM 17,015 Da, 17,061 Da, 17,138 Da and 17,259 Da. DLS and LSI revealed an isoeletric point (pI) of oxy-HbAg of 6.0 +/- 0.3 and 5.5, respectively. Data analysis by IEF-SDS-PAGE revealed that the pI of oxy-HbAg is 6.11, correlating with DLS and LSI data. These studies indicate that oxy-HbAg is very stable, at pH 7.0, and has differing properties from orthologous giant hemoglobins. (AU)

• FAPESP's process: 16/10884-1 - Structural characterization of the extracellular hemoglobin Amynthas gracilis (HbAg) by various biophysics techniques
• Grantee: Jonathan Brito Souza de Oliveira
• Support Opportunities: Scholarships in Brazil - Master
• FAPESP's process: 15/11447-1 - Biophysical characterization of Amynthas gracilis hemoprotein and its potential use as biosensor of environmental contamination
• Grantee: Patrícia Soares Santiago
• Support Opportunities: Research Grants - Young Investigators Grants