1H, 13C and 15N NMR assignments of self-incompatibility protein homologue 15 from Arabidopsis thaliana

Rachel J Coulthard,Karthik V Rajasekar,Jon P Ride,Lorna J Smith,Eva I Hyde

doi:10.1007/s12104-018-9853-0

Rachel J Coulthard, Karthik V Rajasekar + Show 3 more

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https://doi.org/10.1007/s12104-018-9853-0

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Abstract

The SPH proteins are a large family of small, disulphide-bonded, secreted proteins, originally found to be involved in the self-incompatibility response in the field poppy (Papaver rhoeas). They are now known to be widely distributed in plants, many containing multiple members of this protein family. Apart from the PrsS proteins in Papaver the function of these proteins is unknown but they are thought to be involved in plant development and cell signalling. There has been no structural study of SPH proteins to date. Using the Origami strain of E. coli, we cloned and expressed one member of this family, SPH15 from Arabidopsis thaliana, as a folded thioredoxin-fusion protein, purified it from the cytosol, and cleaved it to obtain the secreted protein. We here report the assignment of the NMR spectra of SPH15, which contains 112 residues plus three N-terminal amino acids from the vector. The secondary structure propensity from TALOS+ shows that it contains eight beta strands and connecting loops. This is largely in agreement with predictions from the amino acid sequence, which show an additional C-terminal strand.

Highlights

The S proteins of poppy, Papaver rhoeas, called PrsS, were initially identified as the stigmatic component of the self-incompatibility response (Foote et al 1994)
Several years after the discovery of the S proteins in Papaver, analysis of the genomic sequence of Arabidopsis thaliana revealed a set of genes with homology to the self-incompatibility alleles of P. rhoeas (Ride et al 1999)
As A. thaliana does not exhibit self-incompatibility and, given the taxonomic distance between Papaver and Arabidopsis, the discovery of these homologous genes in Arabidopsis and Papaver suggested that this gene family might be widespread within higher plants and have a larger role than just self-incompatibility

Summary

Introduction

The S proteins of poppy, Papaver rhoeas, called PrsS, were initially identified as the stigmatic component of the self-incompatibility response (Foote et al 1994). Keywords SPH proteins · PrsS · Self-incompatibility · Plant development Several years after the discovery of the S proteins in Papaver, analysis of the genomic sequence of Arabidopsis thaliana revealed a set of genes with homology to the self-incompatibility alleles of P. rhoeas (Ride et al 1999).

Results

Conclusion