6IX1

Structure of 2S albumin seed protein from Dolichos

Summary for 6IX1

• Entry DOI: 10.2210/pdb6ix1/pdb
• Descriptor: 2S Albumin protein, SULFATE ION (3 entities in total)
• Functional Keywords: 2s albumin, beta sheet, plant protein
• Biological source: Dolichos
• Total number of polymer chains: 3
• Total formula weight: 75411.66

Authors

Sharma, S.C.,Kumar, A.,Salunke, D.M. (deposition date: 2018-12-08, release date: 2019-12-11, Last modification date: 2023-11-22)

Primary citation

Sharma, S.C.,Kumar, A.,Vashisht, S.,Salunke, D.M.
High resolution structural and functional analysis of a hemopexin motif protein from Dolichos.
Sci Rep, 9:19828-19828, 2019

PubMed Abstract: It is increasingly evident that seed proteins exhibit specific functions in plant physiology. However, many proteins remain yet to be functionally characterized. We have screened the seed proteome of Dolichos which lead to identification and purification of a protein, DC25. The protein was monomeric and highly thermostable in extreme conditions of pH and salt. It was crystallized and structure determined at 1.28 Å resolution using x-ray crystallography. The high-resolution structure of the protein revealed a four-bladed β-propeller hemopexin-type fold containing pseudo four-fold molecular symmetry at the central channel. While the structure exhibited homology with 2S albumins, variations in the loops connecting the outermost strands and the differences in surface-charge distribution may be relevant for distinct functions. Comparative study of the protein with other seed hemopexins revealed the presence of four conserved water molecules in between the blades which cross-link them and maintain the tertiary structure. The protein exhibited intrinsic peroxidase activity, which could be inhibited by binding of a heme analog. The identification of redox-sensitive cysteine and inhibition of peroxidase activity by iodoacetamide facilitated characterization of the possible active site. The determined peroxidase activity of DC25 may be responsible for rescuing germinating seeds from oxidative stress.

PubMed: 31882615
DOI: 10.1038/s41598-019-56257-6

Experimental method

X-RAY DIFFRACTION (1.28 Å)