Proton and phosphorus-31 magnetic relaxation studies on the interaction of polyriboadenylic acid with Mn2+

Proton and phosphorus-31 nuclear spin–lattice relaxation times T₁ and spin–spin relaxation times T₂ have been measured on the single-stranded polyriboadenylic acid [poly(A)]–Mn²⁺ system in a neutral D₂O solution in the temperature range 10°–90°C at 100 and 40.5 MHz, respectively, with the Fourier transform nmr method. Minimum values of T₁ have been found for all these nuclei, which have enabled the exact estimation of apparent distances from Mn²⁺ to H₂, H₈, H_1′, and the phosphorus nucleus to be 4.7, 4.1, 5.2, and 3.0 Å, respectively. The electron spin of Mn²⁺ penetrates into the phosphorus nucleus, giving ³¹P hyperfine coupling of more than 10⁶ Hz. Evidence of penetration of the electron spin into H₈ and H₂ is also obtained, suggesting direct coordination of nitrogen atoms of the adenine ring to the Mn²⁺ Ion. Combined with the result from proton relaxation enhancement of water, it is concluded that every Mn²⁺ ion added is bound directly to two phosphate groups with a Mn²⁺–phosphorus distance of 3.3 Å, while a part of the Mn²⁺ ions are simultaneouly bound to the adenine ring. It is estimated that 39 ± 13% and 13 ± 5% of Mn²⁺ are coordinated by N₇ and N₃ (or N₁), respectively. The motional freedom of poly(A) in the environment of the Mn²⁺ binding site has been found to be quenched to the extent that the rotational motion becomes several times slower than that of the corresponding Mn²⁺–free poly(A). The activation energies for the molecular motion are, however, practically unchanged from those for Mn²⁺–free poly(A), and are found to be 8.3, 8.5, 6.1, and 8.7 kcal/mol for H₈, H₂, H_1′, and phosphorus, respectively. T₂ of phosphorus is determined by the dissociation rate (k_?1) of Mn²⁺ from the phosphate group for the whole temperature range studied with activation enthalpy of 6.5 kcal/mol. The dissociation rates of Mn²⁺ from the adenine ring are also estimated from proton T₂ values below 50°C.     

Interaction of Aplysia brasiliana Myoglobin with Mn2+ and Cu2+ ions

Myoglobin of Aplysia brasiliana (MbApB) has been recently purified and characterized and it was shown that the amino acid content is quite different from other myoglobins. A large number of aromatic residues was observed together with the existence of a unique histidine at the proximal heme position. Because of the numerous differences in the amino acid sequence between MbApB and whale myoglobin, it was interesting to investigate the interaction of metal ions like Cu²⁺ and Mn²⁺ with MbApB. In the present work Cu²⁺ complexes with Met-MbApB were studied and show a pH transition between different forms of coordination as revealed by EPR measurements. At high pH the EPR spectrum shows the coordination of the metal to at least four nitrogens from ϵ-NH₃ lysine residues. At lower pH in the range 6.0–9.0 the copper binding site shows a pK change of some of the residues involved in metal coordination. Addition of one equivalent Cu²⁺ per protein does not alter the iron EPR signal. The manganese ion has one binding site in MbApB and a binding constant K_a = ( 11.5 ± 0.8) 10³M⁻¹. The binding of Cu²⁺ to MbApB is stronger than Mn²⁺, K_a^Cu2+ >K_a^Mn2+.     

Complexes of (dG-dC)20 with Mn2+ Ions: A Study by Vibrational Circular Dichroism and Infrared Absorption Spectroscopy

Abstract

The B-Z transition of the synthetic oligonucleotide, (dG-dC)₂₀, induced by Mn²⁺ ions at room temperature, was investigated by absorption and Vibrational Circular Dichroism (VCD) spectroscopy in the range of 1800–800 cm^?1. Metal ion concentration was varied from 0 to 0.73 M Mn²⁺ (0 to 8.5 moles of Mn²⁺ per mole of oligonucleotide phosphate, [Mn]/[P]). While both types of spectra showed considerable changes as the Mn²⁺ concentrations were raised, differences between the two were often complementary in their expression and extent, those displayed by VCD being more clearly evident due to the inversion of the opposite helical sense from the right-handed to the left-handed conformation. The main phase of the transition occurred in the metal ion concentration between 0.8?1.1 [Mn]/[P]. Gradual changes that took place in the spectra were interpreted in terms of simultaneous processes that depended on metal ion concentration, namely B-Z transformation, binding of Mn²⁺ to phosphates and to nitrogen bases, and partial denaturation. Below～0.6 [Mn]/[P], only a small portion of the oligonucleotide adopted the Z conformation within a 3 hour period, whereas conversion was completed in the same time interval for concentrations between 0.9?1.2 [Mn]/[P]. At [Mn]/[P] > 1.7, complete transition to the Z-form took place immediately on adding Mn²⁺. Applying VCD spectroscopy in combination with conventional infrared absorption proved most useful for corroborating changes in the absorption spectra, and for detecting in an unique manner, not attainable by absorption methods, conformational changes that lead to the inversion of the helical sense of the oligonucleotide.     

Crystal structures of Bacillus stearothermophilus adenylate kinase with bound Ap5A,Mg2+ Ap5A,and Mn2+ Ap5A reveal an intermediate lid position and six coordinate octahedral geometry for bound Mg2+ and Mn2+

Crystal structures of Bacillus stearothermophilus adenylate kinase with bound Ap₅A, Mn²⁺ Ap₅A, and Mg²⁺ Ap₅A have been determined by X-ray crystallography to resolutions of 1.6 Å, 1.85 Å, and 1.96 Å, respectively. The protein's lid domain is partially open, being both rotated and translated away from bound Ap₅A. The flexibility of the lid domain in the ternary state and its ability to transfer force directly to the the active site is discussed in light of our proposed entropic mechanism for catalytic turnover. The bound Zn²⁺ atom is demonstrably structural in nature, with no contacts other than its ligating cysteine residues within 5 Å. The B. stearothermophilus adenylate kinase lid appears to be a truncated zinc finger domain, lacking the DNA binding finger, which we have termed a zinc knuckle domain. In the Mg²⁺ Ap₅A and Mn²⁺ Ap₅A structures, Mg²⁺ and Mn²⁺ demonstrate six coordinate octahedral geometry. The interactions of the Mg²⁺-coordinated water molecules with the protein and Ap₅A phosphate chain demonstrate their involvement in catalyzing phosphate transfer. The protein selects for β-γ (preferred by Mg²⁺) rather than α-γ (preferred by Mn²⁺) metal ion coordination by forcing the ATP phosphate chain to have an extended conformation. Proteins 32:276–288, 1998. © 1998 Wiley-Liss, Inc.     

Mn2+ reduces Yz + in manganese-depleted Photosystem II preparations

Manganese in the oxygen-evolving complex is a physiological electron donor to Photosystem II. PS II depleted of manganese may oxidize exogenous reductants including benzidine and Mn²⁺. Using flash photolysis with electron spin resonance detection, we examined the room-temperature reaction kinetics of these reductants with Y_z ⁺, the tyrosine radical formed in PS II membranes under illumination. Kinetics were measured with membranes that did or did not contain the 33 kDa extrinsic polypeptide of PS II, whose presence had no effect on the reaction kinetics with either reductant. The rate of Y_z ⁺ reduction by benzidine was a linear function of benzidine concentration. The rate of Y_z ⁺ reduction by Mn²⁺ at pH 6 increased linearly at low Mn²⁺ concentrations and reached a maximum at the Mn²⁺ concentrations equal to several times the reaction center concentration. The rate was inhibited by K⁺, Ca²⁺ and Mg²⁺. These data are described by a model in which negative charge on the membrane causes a local increase in the cation concentration. The rate of Y_z ⁺ reduction at pH 7.5 was biphasic with a fast 400 s phase that suggests binding of Mn²⁺ near Y_z ⁺ at a site that may be one of the native manganese binding sites.Abbreviations PS II Photosystem II - Y_D tyrosine residue in Photosystem II that gives rise to the stable Signal II EPR spectrum - Y_z tyrosine residue in Photosystem II that mediates electron transfer between the reaction center chlorophyll and the site of water oxidation - ESR electron spin resonance - DPC diphenylcarbazide - DCIP dichlorophenolindophenol     

A Neutron Scattering Study of the Ternary Complex EF-Tu•GTP-valy1-tRNAVal 1A

Abstract

The complex formation between elongation factor Tu (EF-Tu), GTP, and valyl-tRNA^Val _1A has been investigated in a hepes buffer of “pH” 7.4 and 0.2 M ionic strength using the small-angle neutron scattering method at concentrations of D₂O where EF-Tu (42% D₂O) and tRNA (71% D₂O) are successively matched by the solvents. The results indicate that EF-Tu undergoes a conformational change and contracts as a result of the complex formation, since the radius of gyration decreases by 15% from 2.82 to 2.39 nm. tRNA^Val _1A, on the other hand, seems to mainly retain its conformation within the complex, since the radii of gyration for the free (after correction for interparticular scattering) and complexed form are essentially the same. 2.38 and 2.47 nm, respectively.     

Interactions of DNA with divalent metal ions. I. 31P-nmr studies

³¹P-nmr has been used to investigate the specific interaction of three divalent metal ions, Mg²⁺, Mn²⁺, and Co⁺², with the phosphate groups of DNA. Mg²⁺ is found to have no significant effect on any of the ³¹P-nmr parameters (chemical shift, line-width, T₁, T₂, and NOE) over a concentration range extending from 20 to 160 mM. The two paramagnetic ions, Mn²⁺ and Co²⁺, on the other hand, significantly change the ³¹P relaxation rates even at very low levels. From an analysis of the paramagnetic contributions to the spin–lattice and spin–spin relaxation rates, the effective internuclear metal–phosphorus distances are found to be 4.5 ± 0.5 and 4.1 ± 0.5 Å for Mn²⁺ and Co²⁺, respectively, corresponding to only 15 ± 5% of the total bound Mn²⁺ and Co²⁺ being directly coordinated to the phosphate groups (inner-sphere complexes). This result is independent of any assumptions regarding the location of the remaining metal ions which may be bound either as outer-sphere complexes relative to the phosphate groups or elsewhere on the DNA, possibly to the bases. Studies of the temperature effects on the ³¹P relaxation rates of DNA in the absence and presence of Mn²⁺ and Co²⁺ yielded kinetic and thermodynamic parameters which characterize the association and dissociation of the metal ions from the phosphate groups. A two-step model was used in the analysis of the kinetic data. The lifetimes of the inner-sphere complexes are 3 × 10^?7 and 1.4 × 10^?5 s for Mn²⁺ and Co²⁺, respectively. The rates of formation of the inner-sphere complexes with the phosphate are found to be about two orders of magnitude slower than the rate of the exchange of the water of hydration of the metal ions, suggesting that expulsion of water is not the rate-determining step in the formation of the inner-sphere complexes. Competition experiments demonstrate that the binding of Mg²⁺ ions is 3–4 times weaker than the binding of either Mn²⁺ or Co²⁺. Since the contribution from direct phosphate coordination to the total binding strength of these metal ion complexes is small (～15%), the higher binding strength of Mn²⁺ and Co²⁺ may be attributed either to base binding or to formation of stronger outer-sphere metal–phosphate complexes. At high levels of divalent metal ions, and when the metal ion concentration exceeds the DNA–phosphate concentration, the fraction of inner-sphere phosphate binding increases. In the presence of very high levels of Mg²⁺ (e.g., 3.1M), the inner-sphere ? outer-sphere equilibrium is shifted toward ～100% inner-sphere binding. A comparison of our DNA results and previous results obtained with tRNA indicates that tRNA and DNA have very similar divalent metal ion binding properties. A comparison of the present results with the predictions of polyelectrolyte theories is presented.     

Location of Mn2+ in concanavalin A containing only a Mn2+ ion

The metal-sugar distances in two metallized forms of concanavalin A have been compared by ¹⁹F magnetic resonance techniques. Using relaxation times measured at two different frequencies we have shown that the distance between the Mn²⁺ ion and the bound sugar in concanavalin A containing only Mn²⁺ is essentially identical to that found in concanavalin A containing both Mn²⁺ and Ca²⁺. Our results rule out the possibility that Mn²⁺ activates concanavalin A by binding at the Ca²⁺ site (S2) and would suggest that Mn²⁺ alone can induce an active saccharide binding conformation by binding at the transition metal site (S1).     

Sequence studies on human placenta tRNAVal : comparison with the mouse myeloma tRNAVal

The major species of valine specific tRNA was isolated from human placenta, degraded to oligonucleotides, and shown to have the nucleotide sequence pG-U-U-U-C-C-G-U-A-G-U-G-U?-A-G-D-G-G-D-D-A-U-C-A-C-m²G-U?-U-C-G-C-C-U-(I or C)-A-C-A-C-G-C-G-A-A-A-G-m⁷G-D-m⁵C-m⁵C-C-C-G-G-U-U?-C-G-m¹A-A-A-C-C-G-G-G-C-G-G-A-A-A-C-A-C-C-A_OH. This human placental tRNA^Val differs from the major species of mouse myeloma tRNA^Val only in that it contains either I or C in the wobble position of the anticodon, and totally lacks 2′-O-methylcytosine and 5-methylcytosine in the anticodon loop.     

Tunable luminescence and energy transfer in Ca3SiO4Cl2:Ce3+,Li+,Mn2+,Eu2+ phosphors

A series of color‐tunable Ca_{3–2x‐y‐z}SiO₄Cl₂ (CSC):xCe³⁺,xLi⁺,yMn²⁺,zEu²⁺ phosphors with low temperature phase structure was synthesized via the sol–gel method. An energy transfer process from Ce³⁺ to Mn²⁺ in CSC:0.01Ce³⁺,0.01Li⁺,yMn²⁺ (y = 0.03–0.09) and the mechanism was verified to be an electric dipole–dipole interaction. The Ce³⁺ and Mn²⁺ emission intensities were greatly enhanced by co‐doping Eu²⁺ ions into CSC:0.01Ce³⁺,0.01Li⁺,0.07Mn²⁺ phosphors due to competitive energy transfers from Eu²⁺/Ce³⁺ to Mn²⁺, and Ce³⁺ to Eu²⁺. Under 332 nm excitation, CSC:0.01Ce³⁺,0.01Li+,0.07Mn²⁺,zEu²⁺ (z = 0.0005–0.002) exhibited tunable emission colors from green to white with coexisting orange, green and violet‐blue emissions. These phosphors could have potential application in white light‐emitting diodes.     

Phosphors Ba2LaTaO6:Mn4+ and its alkali metal charge compensation for plant growth illumination

A series of Mn⁴⁺-doped and Mn⁴⁺,K⁺-co-doped Ba₂LaTaO₆ (BLT) double-perovskite phosphors was synthesized using a high-temperature solid-state reaction. The phase purity and luminescence properties were also studied. The optimum doping concentration of Mn⁴⁺ and K⁺ was obtained by investigating the photoluminescence excitation spectra and photoluminescence emission spectra. The comparison of BLT:Mn⁴⁺ phosphors with and without K⁺ ions shows that the photoluminescence intensity of K⁺-doped phosphors was greatly enhanced. This is because there was a charge difference when Mn⁴⁺ ions were doped with Ta⁵⁺ ions in BLT. Mn⁴⁺–K⁺ ion pairs were formed after doping K⁺ ions, which hinders the nonradiative energy transfer between Mn⁴⁺ ions. Therefore, the luminescence intensity, quantum yield, and thermal stability of phosphors were enhanced. The electroluminescence spectra of BLT:Mn⁴⁺ and BLT:Mn⁴⁺,K⁺ were measured. The spectra showed that the light emitted from the phosphors corresponded well with chlorophyll a and phytochrome P_R. The results show that the BLT:Mn⁴⁺,K⁺ phosphors had good luminescence properties and application prospects and are ideal materials for plant-illuminated red phosphors.     

Light-induced Mn2+ influx in Limulus ventral photoreceptors

In contrast to insect species, light-activated influx of divalent ions into Limulus ventral photoreceptors has proven difficult to demonstrate. We used the quench of the fluorescent indicator dye, fura-2, to measure Mn²⁺ influx. Limulus ventral photoreceptors were injected with fura-2 and excited at 360 nm. When the photoreceptors were bathed in 1 mmol · l⁻¹ Mn²⁺, an approximately 1% per 10 s decline in the fura-2 fluorescence during intervals between 50-ms flashes was taken as a measure of Mn²⁺ entry in darkness. Fluorescence decline during 10-s flashes was used to monitor Mn²⁺ entry during the photoresponse. During the 10-s flashes we observed a small rapid decline of the fura-2 fluorescence even in the absence of Mn²⁺. This reflected a contamination of the fluorescence signal arising from light-induced release of intracellular calcium stores. A subsequent slower decline in fluorescence during the 10-s flash, amounting to approximately 9% per 10 s, was only observed in the presence of extracellular Mn²⁺ and was attributed to Mn²⁺ influx. This light-activated influx was not through voltage-gated calcium channels since it persisted under voltage clamp, was not stimulated by depolarizing current injections, nor blocked by NiCl₂. Depletion of internal calcium stores by cyclopiazonic acid treatment did not accelerate Mn²⁺ influx. Accepted: 30 January 1998     

A novel Mn4+-activated far-red Sr2MgWO6 phosphor: synthesis,luminescence enhancement,and application prospect

A novel far-red emitting phosphor Sr₂MgWO₆: Mn⁴⁺ was fabricated using high-temperature solid-state reaction. X-ray diffraction patterns, scanning electron microscopy images, and photoluminescence excitation and photoluminescence spectra for this phosphor were analyzed in detail. The analysis revealed that its emission ranged from 600 to 800 nm and peaked at 699 nm, which was attributed to the ²E_g→⁴A_2g transition of Mn⁴⁺ under 314 nm excitation. Moreover, we introduced rare-earth Yb³⁺ ions into the Sr₂MgWO₆:Mn⁴⁺ to improve its far-red emitting intensity. The photoluminescence (PL) intensity of the Yb³⁺ co-doped phosphor was three times higher than that of the single-doped phosphor. Therefore charge compensation is an efficient approach to improving PL intensity. The phosphor emitted a far-red light that resembled the pigments essential for plant growth in terms of the absorption spectrum. Therefore, the obtained phosphor, Sr₂MgWO₆:0.006Mn⁴⁺,0.2Yb³⁺, had the potential to be a new type of far-red luminescent powder for indoor plant growth LEDs.     

Isolation and properties of a Mn2+-activated phosphohistone phosphatase from canine heart.

A Mn²⁺-activated phosphohistone phosphatase has been isolated from canine heart. The s_{20, w} for the enzyme is 3.8. Using this value and the value for Stokes radius (39 Å), the molecular weight for the enzyme was calculated to be 61,000. The enzyme is inactive in the absence of divalent cations, among which Mn²⁺ is the most effective activator. Co²⁺ and Mg²⁺ are less effective than is Mn²⁺. Zn²⁺, Fe²⁺, and Cu²⁺ are inhibitory. The enzyme has a pH optimum between 7 and 7.5 and has an apparent K_m for phosphohistone and Mn²⁺ of about 17 μm and 0.5 mm, respectively. The enzyme is inhibited by nucleoside triphosphate, ADP, AMP, phosphate, and pyrophosphate, but is not affected by cyclic AMP or cyclic GMP. The dephosphorylation of phosphohistone is stimulated by salts. Kinetic studies reveal that KCl and other salts greatly affect both the rate of hydrolysis and the K_m for either Mn²⁺ or phosphohistone by interacting with the substrate. The data suggest that modification at substrate level is an important regulatory mechanism for the enzyme. The enzyme preparation also dephosphorylates phosphorylase a and phosphocasein. Evidence suggests that one enzyme possesses both phosphohistone and phosphorylase phosphatase activities and that a different enzyme catalyzes the Mg²⁺- and Mn²⁺-activated dephosphorylation of phosphocasein.     

Location of two Mn2+ affinity sites in photosystem II detected by pulsed electron–electron double resonance

In this study, we identified two Mn²⁺ sites in apo-Photosystem II (PSII) using the pulsed electron–electron double resonance (PELDOR). A Mn²⁺ ion was bound to apo-PSII on the deactivation of the oxygen-evolving complex. The electron–electron magnetic dipole interaction of the Mn²⁺ to Y_D^· was estimated to be 2.4 MHz. The site was assigned at the position between His332 and Glu189 in the D1 polypeptide, which is close to the Mn1 site in mature PS II. Using recent structures observed under electron microscopes (EM), the location of the Mn²⁺ site on photoactivation was reevaluated. The position between Asp170 and Glu189 in the D1 polypeptide is a good candidate for the initial high-affinity site for photoactivation. Based on a comparison with the PELDOR results, the two EM structures were evaluated.

     

Effect of temperature on intense green emitting Na2Ca(PO4)F:Mn2+ phosphor

An intense green luminescent Na₂Ca(PO₄)F:Mn²⁺ phosphor has been prepared at high temperature by reduction treatment in a charcoal environment. The emission band of Mn²⁺ was obtained at around 522 nm (green) under 259 nm excitation. Enhancement in emission intensity arising from the thermal treatment is reported. The intense emission of the spectrum was assigned to electronic transitions ⁴T₁ → ⁶A₁ of Mn²⁺ ions. Intense PL emission suggested that temperature employed plays an important role in the present matrix. X‐ray diffraction pattern, photoluminescence and morphology by SEM of the host lattice of phosphors at different temperatures have been reported in this paper. The results obtained show that the present phosphor has potential for application in green emitting phosphors for the lamp industry. Copyright © 2010 John Wiley & Sons, Ltd.     

Effects of calcium and manganese ions on the helix–coil transition of DNA

The thermal denaturation method was employed to study the effect of Ca²⁺ and Mn²⁺ ions on the DNA helix–coil transition parameters at Na⁺ concentrations of 10^?3–10^?1M. At low ion concentrations, thermal stability increases, the melting range passes through a maximum, and the denaturation curves become asymmetric. These changes are quantitatively similar for Mn²⁺ and Ca²⁺ ions. With a further increase in the concentration of bivalent ions, the conformational transition temperatures pass through a maximum, and the melting range first tends to saturation and then rapidly decreases to 1–2°C. The Mn²⁺ concentrations, at which the above effects occur, are an order of magnitude lower than the Ca²⁺ concentrations. Comparison of experimental results and calculation in terms of the ligand theory permitted estimation of binding constants characterizing association between Mn²⁺ and Ca²⁺ ions and bases of native and denatured DNA. We show that, unlike the interaction with phosphates, bivalent ion–DNA base binding is weakly dependent on monovalent ion concentration in the solution.     

Energy coupling in Mn2+ oxidation by a marine bacterium

ATP synthesis couple to Mn²⁺ oxidation was demonstrated with partially or wholly everted membrane vesicles from marine bacterial strain SSW₂₂. The extent of ATP synthesis in these experiments was greater in earlier experiments. Chemiosmosis is the most probable mechanism for energy coupling because 2,4-dinitrophenol at appropriate concentrations stimulated Mn²⁺ oxidation by intact cells, membrane vesicles or extracts of strains SSW₂₂, S₁₃, and marine pseudomonad 16B. Externally added ADP stimulated Mn²⁺ oxidation by everted membrane vesicles of strain SSW₂₂. This stimulation was oxygen-dependent. It is explained on the basis of a chemiosmotic model for energy coupling in Mn²⁺ oxidation.     

Distribution of Mn2+ ions around poly(rI).poly(rC)

The distribution of bound Mn²⁺ ions about poly(rI)·poly(rC) has been studied by measuring the effect of this paramagnetic metal ion on the relaxation behavior of poly(rI)·poly(rC) protons. By combining selective spin – lattice and spin – spin relaxation rates for various protons, some of the principle regions of ion association can be identified. The relaxation data on the CH6 proton are consistent with a < 10% occupancy of phosphate inner-sphere binding sites. The broadening of the imino proton resonance requires a substantial occupancy of sites located in the major groove, possibly near IN7. This would also be consistent with the observation that IH8 resonance is the proton most susceptible to relaxation by Mn²⁺. The relaxation data for the IH2 proton indicate a relatively low occupancy of minor-groove binding sites (e.g., IN3).     

Intense green light emission in Sr2ZnGe2O7:Mn2+ phosphors by the design of high symmetry melilite structure

A green phosphor Sr₂ZnGe₂O₇:Mn²⁺ with a melilite structure was prepared using a high-temperature solid-state reaction. When the 535 nm emission was monitored, the excitation spectrum of the Sr₂ZnGe₂O₇:Mn²⁺ was found to contain two excitation bands in the ultraviolet (UV) region. When excited by UV light, the sample shows bright green emission at 535 nm, which corresponds to the distinctive transition of Mn²⁺ (⁴T₁→⁶A₁). Moreover, the quantum efficiency of Sr₂ZnGe₂O₇:Mn²⁺ could reach 67.6%. Finally, a high-performance white-light-emitting diode (WLED) with a low correlated colour temperature of 4632 K and a high colour rendering index (CRI) of 92.3 were packaged by coating commercial blue and red phosphors with an optimized Sr₂ZnGe₂O₇:Mn²⁺ sample on a 310 nm UV chip. This indicated that Sr₂ZnGe₂O₇:Mn²⁺ has the potential application as a green component in the WLED lighting field.