8H17

Crystal structure of the Globin domain of Thermosynechococcus elongatus BP-1

Summary for 8H17

• Entry DOI: 10.2210/pdb8h17/pdb
• Descriptor: Tlr1989 protein, IMIDAZOLE, PROTOPORPHYRIN IX CONTAINING FE, ... (4 entities in total)
• Functional Keywords: thermosynechococcus vestitus bp-1, haemoglobin, imidazole, penta-cordinated heme, heme binding, iron, thermophile, cyanobacteria, synechococcus, oxygen binding
• Biological source: Thermosynechococcus vestitus BP-1
• Total number of polymer chains: 1
• Total formula weight: 23529.91

Authors

Mathur, S.,Yadav, S.K.,Pal, K.R.,Kundu, S. (deposition date: 2022-09-30, release date: 2023-04-26, Last modification date: 2024-05-01)

Primary citation

Mathur, S.,Yadav, S.K.,Yadav, K.,Bhatt, S.,Kundu, S.
A novel single sensor hemoglobin domain from the thermophilic cyanobacteria Thermosynechococcus elongatus BP-1 exhibits higher pH but lower thermal stability compared to globins from mesophilic organisms.
Int.J.Biol.Macromol., 240:124471-124471, 2023

PubMed Abstract: Thermosynechococcus elongatus-BP1 belongs to the class of photoautotrophic cyanobacterial organisms. The presence of chlorophyll a, carotenoids, and phycocyanobilin are the characteristics that categorize T. elongatus as a photosynthetic organism. Here, we report the structural and spectroscopic characteristics of a novel hemoglobin (Hb) Synel Hb from T.elongatus, synonymous with Thermosynechococcus vestitus BP-1. The X-ray crystal structure (2.15 Å) of Synel Hb suggests the presence of a globin domain with a pre-A helix similar to the sensor domain (S) family of Hbs. The rich hydrophobic core accommodates heme in a penta-coordinated state and readily binds an extraneous ligand (imidazole). The absorption and circular dichroic spectral analysis of Synel Hb reiterated that the heme is in Fe state with a predominantly α-helical structure similar to myoglobin. Synel Hb displays higher resistance to structural perturbations induced via external stresses like pH and guanidium hydrochloride, which is comparable to Synechocystis Hb. However, Synel Hb exhibited lower thermal stability compared to mesophilic hemoglobins. Overall, the data is suggestive of the structural sturdiness of Synel Hb, which probably corroborates its origin in extreme thermophilic conditions. The stable globin provides scope for further investigation and may lead to new insights with possibilities for engineering stability in hemoglobin-based oxygen carriers.

PubMed: 37076076
DOI: 10.1016/j.ijbiomac.2023.124471

Experimental method

X-RAY DIFFRACTION (2.15 Å)