Structural-functional analysis of the oligomeric protein R-phycoerythrin

Martínez‐Oyanedel, José; Contreras‐Martel, Carlos; Bruna, Carola; Bunster, Marta

doi:10.4067/s0716-97602004000500003

Cited by 18 publications

(8 citation statements)

References 20 publications

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“…Aspartic acids (D α 13 , D β 13 , D β 39 ) interact with A and D rings of the respective chromophore. The involvement of Aspartic acids maintaining the curvature of phycobilins has been reported in all the phycobiliproteins [7,44] and it may be a relevant feature for the biological activity. The docking procedure performed by ZDOCK [29] involved a rigid body interaction of two hexamers of phycocyanin (PC).…”

Section: Resultsmentioning

confidence: 99%

The structure at 2 Å resolution of Phycocyanin from Gracilaria chilensis and the energy transfer network in a PC–PC complex

Contreras‐Martel

Matamala

Bruna

et al. 2007

Biophysical Chemistry

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Phycocyanin is a phycobiliprotein involved in light harvesting and conduction of light to the reaction centers in cyanobacteria and red algae. The structure of C-phycocyanin from Gracilaria chilensis was solved by X-ray crystallography at 2.0 Å resolution in space group P2 1 . An interaction model between two PC heterohexamers was built, followed by molecular dynamic refinement. The best model showed an inter-hexamer rotation of 23°. The coordinates of a PC heterohexamer (αβ) 6 and of the PC-PC complex were used to perform energy transfer calculations between chromophores pairs using the fluorescence resonance energy transfer approach (FRET). Two main intra PC (

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Section: Resultsmentioning

confidence: 99%

The structure at 2 Å resolution of Phycocyanin from Gracilaria chilensis and the energy transfer network in a PC–PC complex

Contreras‐Martel

Matamala

Bruna

et al. 2007

Biophysical Chemistry

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“…All these comprise faster decreases in the absorbance at 565 nm reflecting gradual reductions in absorption capability of the PEBs and their interactions with proteins. More significant decreases in absorbance are observed when the urea concentration is above 3.0 M. However, all these reductions in absorbance are attributed to PEBs and their interactions with the proteins, as reported earlier (Martinez-Oyanedel et al, 2004). Above 6 M of urea concentration, the peaks of both the proteins get vanished leaving very low absorption.…”

Section: Structural and Thermodynamic Characterizationsmentioning

confidence: 59%

Role of N-terminal residues on folding and stability of C-phycoerythrin: simulation and urea-induced denaturation studies

Anwer

Sonani

Madamwar

et al. 2013

Journal of Biomolecular Structure and Dynamics

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The conformational state of biliproteins can be determined by optical properties of the covalently linked chromophores. Recently determined crystal structure of truncated form of α-subunit of cyanobacterial phycoerythrin (αC-PE) from Phormidium tenue provides a new insight into the structure-function relationship of αC-PE. To compare their stabilities, we have measured urea-induced denaturation transitions of the full length αC-PE (FL-αC-PE) and truncated αC-PE (Tr-αC-PE) followed by observing changes in absorbance at 565 nm, fluorescence at 350 and 573 nm, and circular dichroism at 222 nm as a function of [urea], the molar concentration of urea. The transition curve of each protein was analyzed for ΔG(D)(0), the value of Gibbs free energy change on denaturation (ΔG(D)) in the absence of urea; m, the slope (=∂∆G(D)/∂[urea]), and C(m), the midpoint of the denaturation curve, i.e. [urea] at which ΔG(D) = 0. A difference of about 10% in ΔG(D)(0) observed between FL-αC-PE and Tr-αC-PE, suggests that the two proteins are almost equally stable, and the natural deletion of 31 residues from the N-terminal side of the full length protein does not alter its stability. Furthermore, normalization of probes shows that the urea-induced denaturation of both the proteins is a two-state process. Folding of both structural variants (Tr-αC-PE and FL-αC-PE) of P. tenue were also studied using molecular dynamics simulations at 300 K. The results show clearly that the stability of the proteins is evenly distributed over the whole structure indicating no significant role of N-terminal residues in the stability of both proteins.

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“…PBPs, PE in particular has been observed to be extremely sensitive towards desiccation (drying), besides light, salts, pH, temperature, etc., leading up to 5-60% loss in content (Potts 1994;Sarada et al 1999;Sun et al 2003;Martinez-Oyanedel et al 2004). Dissociation of the PBPs results in marked variations in their spectroscopic characteristics (Gantt et al 1979;Anderson et al 1983;Wang et al 1997), and decreases not only the extinction coefficient and quantum yield, but also lowers the probability of formation of cross links with the target biomolecules while developing conjugates (Sun et al 2003;Yeh et al 1987).…”

Section: Resultsmentioning

confidence: 96%

“…R-PE is mostly obtained from marine algae, mainly from the Rhodophyceae. Moreover, while processing for extraction, purification, storage and utilization, PEs are highly sensitive to variations in pH, salts, temperature, water stress and light (Potts 1994;Sarada et al 1999;Sun et al 2003;Martinez-Oyanedel et al 2004) thus impeding applications of the product. To some extent, problems of storage stability of PEs, which are a matter of great concern, have been met by applying ammonium sulfate precipitation or lyophilization (http: // www.invitrogen.com, probes.invitrogen.com, http://www.…”

Section: Introductionmentioning

confidence: 98%

Extraction and purification of an unusual phycoerythrin in a terrestrial desiccation tolerant cyanobacterium Lyngbya arboricola

2007

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Presence and stability of an unusual phycoerythrin (PE) characteristically similar to R-PE are described in a terrestrial, desiccation-tolerant cyanobacterium, Lyngbya arboricola. Extraction and purification of the PE by using acetone precipitation, gel filtration and ion-exchange chromatography resulted in achieving a purity index (A 560 /A 280 ) of up to 5.2. SDS-PAGE of the PE showed presence of 18 kDa, 20 kDa and 32 kDa bands corresponding to a, β and + subunits of R-PE without any other contaminating phycobiliproteins (PBPs). The absorption spectrum of the PE was distinguished by two major peaks at 499 and 559 nm. The maximum fluorescence emission at room temperature was 578 nm. Spectroscopic and electrophoresis characteristics of PE in the dry mats on storage at 25±1°C over silica gel for 2 years remained almost unaffected. Quantitatively, storage stability of the PE was in the order of dry mats > lyophilized > liquid state and the impact of temperature on loss of PE was in the order of 25°C>−20°C> 4°C. The relevance of L. arboricola for production of stable unusual PE is discussed.

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Structural-functional analysis of the oligomeric protein R-phycoerythrin

Cited by 18 publications

References 20 publications

The structure at 2 Å resolution of Phycocyanin from Gracilaria chilensis and the energy transfer network in a PC–PC complex

The structure at 2 Å resolution of Phycocyanin from Gracilaria chilensis and the energy transfer network in a PC–PC complex

Role of N-terminal residues on folding and stability of C-phycoerythrin: simulation and urea-induced denaturation studies

Extraction and purification of an unusual phycoerythrin in a terrestrial desiccation tolerant cyanobacterium Lyngbya arboricola

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