Determination of the Distance Between the Cytochrome and Dehydrogenase Domains of Immobilized Cellobiose Dehydrogenase by Using Surface Plasmon Resonance with a Center of Mass Based Model
Artikel i vetenskaplig tidskrift, 2020

Changes in the tertiary conformation of adsorbed biomolecules can induce detectable shifts (Δθr) in the surface plasmon resonance (SPR) angle. Here it is shown how to calculate the corresponding shifts in the adsorbate's center of mass (Δzavg) along the sensing surface normal from the measured Δθr. The novel developed model was used for determining the mean distance between the cytochrome (CYT) and flavodehydrogenase (DH) domains of the enzyme cellobiose dehydrogenase (CDH) isolated from the fungi Neurospora crassa, Corynascus thermophilus, and Myriococcum thermophilum as a function of pH, [Ca2+], and substrate concentration. SPR confirmed the results from earlier electrochemical and SAXS studies stating that the closed conformation, where the two domains are in close vicinity, is stabilized by a lower pH and an increased [Ca2+]. Interestingly, an increasing substrate concentration in the absence of any electron acceptors stabilizes the open conformation as the electrostatic repulsion due to the reaped electrons pushes the DH and CYT domains apart. The accuracy of distance determination was limited mostly by the random fluctuations between replicate measurements, and it was possible to detect movements <1 nm of the domains with respect to each other. The results agreed with calculations using already established models treating conformational changes as contraction or expansion of the thickness of the adsorbate layer (tprotein). Although the models yielded equivalent results, in this case, the Δzavg-based method also works in situations, where the adsorbate's mass is not evenly distributed within the layer.

Författare

Jani Tuoriniemi

Göteborgs universitet

Lo Gorton

Lunds universitet

Roland Ludwig

Universität für Bodenkultur Wien

Gulnara Safina

Chalmers, Fysik, Biologisk fysik

Göteborgs universitet

Analytical Chemistry

0003-2700 (ISSN) 1520-6882 (eISSN)

Vol. 92 3 2620-2627

Ämneskategorier

Analytisk kemi

DOI

10.1021/acs.analchem.9b04490

PubMed

31916434

Mer information

Senast uppdaterat

2020-02-17