The Protein Journal

, Volume 32, Issue 5, pp 399–410

Two Global Conformation States of a Novel NAD(P) Reductase Like Protein of the Thermogenic Appendix of the Sauromatum guttatum Inflorescence

Article

DOI: 10.1007/s10930-013-9497-y

Cite this article as:
Skubatz, H. & Howald, W.N. Protein J (2013) 32: 399. doi:10.1007/s10930-013-9497-y

Abstract

A novel NAD(P) reductase like protein (RL) belonging to a class of reductases involved in phenylpropanoid synthesis was previously purified to homogeneity from the Sauromatum guttatum appendix. The Sauromatum appendix raises its temperature above ambient temperature to ~30 °C on the day of inflorescence opening (D-day). Changes in the charge state distribution of the protein in electrospray ionization–mass spectrometry spectra were observed during the development of the appendix. RL adopted two conformations, state A (an extended state) that appeared before heat-production (D − 4 to D − 2), and state B (a compact state) that began appearing on D − 1 and reached a maximum on D-day. RL in healthy leaves of Arabidopsis is present in state A, whereas in thermogenic sporophylls of male cones of Encephalartos ferox is present in state B. These conformational changes strongly suggest an involvement of RL in heat-production. The biophysical properties of this protein are remarkable. It is self-assembled in aqueous solutions into micrometer sizes of organized morphologies. The assembly produces a broad range of cyclic and linear morphologies that resemble micelles, rods, lamellar micelles, as well as vesicles. The assemblies could also form network structures. RL molecules entangle with each other and formed branched, interconnected networks. These unusual assemblies suggest that RL is an oligomer, and its oligomerization can provide additional information needed for thermoregulation. We hypothesize that state A controls the plant basal temperature and state B allows a shift in the temperature set point to above ambient temperature.

Keywords

Arabidopsis thalianaConformationEncephalartos feroxNAD(P) reductase-like proteinSauromatum guttatumSelf-assemblyThermoregulation

Abbreviations

ACN

Acetonitrile

BSA

Bovine serum albumin

CSD

Charge state distribution

D-day

The day of inflorescence opening and heat-production

ESI–MS

Electrospray ionization–mass spectrometry

GuHCl

Guanidine hydrochloride

IP

Isopropanol

MaxEnt

Maximum entropy software for deconvolution of multiple charged electrospray envelopes

PVP

Polyvinylpyrrolidone

RL

NAD(P) reductase-like protein

RP-HPLC

Reversed phase-high performance liquid chromatography

SA

Salicylic acid

TFA

Trifluoroacetic acid

Copyright information

© Springer Science+Business Media New York 2013

Authors and Affiliations

  1. 1.NeoPro LabsSeattleUSA
  2. 2.School of Pharmacy Mass Spectrometry Center, Department of Medicinal ChemistryUniversity of WashingtonSeattleUSA