Photosynthetic reaction centers; photodynamic therapy targets (cancer cells)

The bacteriochlorophyll (BChl) a protein from Chlorobium tepidum, which participates in energy transfer in green photosynthetic bacteria, has been crystallized using the sitting drop method of vapor diffusion. X-ray diffraction data collected from these crystals indicate that the crystals belong to the cubic space group P4132 with cell dimensions of a=b=c=169.5 A. A native X-ray diffraction data set has been collected to a resolution of 2.2 A. The initial solution was determined by using the molecular replacement method using the structure of the previously solved BChl a protein from Prosthecochloris aestuarii. A unique rotation and translation solution was obtained for two monomers in the asymmetric unit giving a pseudo-body centered packing. After rebuilding and refinement the model yields an R factor of 19.0%, a free R-factor of 28.3%, and good geometry with root-mean-square deviations of 0.013 A and 2.1 degrees for the bond lengths and angles, respectively. The structure of the BChl a protein from C. tepidum consists of three identical subunits related by a 3-fold axis of crystallographic symmetry. In each subunit the polypeptide backbone forms large beta-sheets and encloses a central core of seven BChl a molecules. The distances between neighboring bacteriochlorin systems within a subunit range between 4 A to 11 A and that between two bacteriochlorins from different subunits is more than 20 A. The overall structure is comparable with that of P. aestuarii but significant differences are observed for the individual bacteriochlorophyll structures. The surface of the trimer has a hydrophobic region that is modeled as the complex being a peripheral membrane protein partially embedded in the membrane. A general model is presented for the membrane organization with two of the bacteriochlorophyll structures in the membrane and transferring energy to the reaction center complex. In this model these two bacteriochlorophyll structures serve a similar role to the cofactors of integral membrane light-harvesting complexes although the protein structure surrounding the cofactors is significantly different for the BChl a protein compared with the integral membrane complexes.[1]

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Bacteriochlorophyll a exhibits strong absorption in the near-infrared region at lambda=770-850 nm. This absorption property enables deeper tissue penetration of light compared to visible wavelengths, making it suitable for photodynamic therapy applications. The compound's photophysical properties allow for efficient energy transfer and generation of reactive oxygen species upon light activation, which can induce cell death in targeted tissues.

In vivo applications of bacteriochlorophyll a are primarily explored in photodynamic therapy research. The compound's near-infrared absorption allows for deeper tissue penetration, increasing the photodamage for tumor eradication. Studies have investigated the use of bacteriochlorophyll derivatives for targeted cancer cell destruction using light activation. The compound's properties are being explored for potential applications in targeting and destroying cancer cells using light.

Photophysical properties including absorption spectra are measured using UV-Vis spectrophotometry to confirm absorption at lambda=770-850 nm. Photosynthetic activity is assessed using fluorescence spectroscopy and oxygen evolution measurements. The compound's ability to generate reactive oxygen species upon light activation is measured using appropriate chemical probes.

Cell-based assays evaluate the photodynamic activity of bacteriochlorophyll a in cancer cell lines. Cells are incubated with the compound and exposed to near-infrared light at 770-850 nm. Cell viability is measured using MTT or CellTiter-Glo assays to assess light-induced cytotoxicity. Reactive oxygen species generation is measured using fluorescent probes to confirm the mechanism of photodynamic activity.

In vivo photodynamic therapy studies are conducted in animal models of cancer. Bacteriochlorophyll a or its derivatives are administered to tumor-bearing animals, followed by near-infrared light irradiation at 770-850 nm. Tumor growth inhibition and tissue damage are assessed to evaluate photodynamic efficacy. The compound's deeper tissue penetration enables treatment of deeper-seated tumors.

Pharmacokinetic data for bacteriochlorophyll a are limited as the compound is primarily used as a research tool and photosensitizer. The compound's unique absorption properties in the near-infrared region influence its tissue distribution and light activation characteristics. Biodistribution studies may be conducted to assess tumor accumulation and clearance.

Comprehensive toxicological data for bacteriochlorophyll a are limited. The compound is used in research applications including photosynthesis studies and photodynamic therapy development. Photodynamic therapy using bacteriochlorophyll derivatives has been explored for cancer treatment, with toxicity primarily related to light-induced damage in targeted tissues. Standard laboratory safety precautions should be observed during handling.

[1]. Crystal structure of the bacteriochlorophyll a protein from Chlorobium tepidum. Journal of molecular biology 271.3 (1997): 456-471.

A type of bacterial chlorophyll with a structure similar to chlorophyll A. A pyrrole-containing pigment found in photosynthetic bacteria.

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Bacteriochlorophyll a is a photosynthetic pigment from phototrophic bacteria that is being explored for photodynamic therapy applications due to its near-infrared absorption properties. The compound's ability to absorb light at 770-850 nm enables deeper tissue penetration, making it potentially useful for treating deeper-seated tumors. It plays a crucial role in studying photosynthetic processes and energy conversion in bacteria. Bacteriochlorophyll a remains a research tool for photosynthesis and photodynamic therapy studies.

C55H74MGN4O6

911.524

910.546

C, 72.47; H, 8.18; Mg, 2.67; N, 6.15; O, 10.53

17499-98-8

18025-10-0

11953947

Solid powder

877.3ºC at 760mmHg

484.4ºC

0mmHg at 25°C

9.449

0

10

22

66

2100

7

[Mg+2].N1=C2C=C3[N-]C(C(=C3C)C(=O)C)=CC3=NC(=CC4=C(C5C(=O)C(C(=O)OC)C(=C1C(CCC(OC/C=C(/CCCC(CCCC(CCCC(C)C)C)C)\C)=O)C2C)C=5[N-]4)C)C(C3C)CC |c:2,12,16,t:28|

DSJXIQQMORJERS-AGGZHOMASA-M

InChI=1S/C55H75N4O6.Mg/c1-13-39-34(7)41-29-46-48(38(11)60)36(9)43(57-46)27-42-35(8)40(52(58-42)50-51(55(63)64-12)54(62)49-37(10)44(59-53(49)50)28-45(39)56-41)23-24-47(61)65-26-25-33(6)22-16-21-32(5)20-15-19-31(4)18-14-17-30(2)3/h25,27-32,34-35,39-40,51H,13-24,26H2,1-12H3,(H-,56,57,58,59,60,62)/q-1+2/p-1/b33-25+/t31-,32-,34-,35+,39-,40+,51-/m1./s1

magnesiummethyl (3R,11R,12R,21S,22S)-16-acetyl-11-ethyl-12,17,21,26-tetramethyl-4-oxo-22-[3-oxo-3-[(E,7R,11R)-3,7,11,15-tetramethylhexadec-2-enoxy]propyl]-23,25-diaza-7,24-diazanidahexacyclo[18.2.1.15,8.110,13.115,18.02,6]hexacosa-1(23),2(6),5(26),8,10(25),13,15,17,19-nonaene-3-carboxylate

C11242C-11242Bacteriochlorophyll a Bacteriochlorophyll Bacteriochlorophyll from Rhodopseudomonas sphaeroides

2934.99.9001

Powder      -20°C    3 years

                     4°C     2 years

In solvent   -80°C    6 months

                  -20°C    1 month

Room temperature (This product is stable at ambient temperature for a few days during ordinary shipping and time spent in Customs)

May dissolve in DMSO (in most cases), if not, try other solvents such as H2O, Ethanol, or DMF with a minute amount of products to avoid loss of samples

Note: Listed below are some common formulations that may be used to formulate products with low water solubility (e.g. < 1 mg/mL), you may test these formulations using a minute amount of products to avoid loss of samples.

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Injection Formulation 1: DMSO : Tween 80： Saline = 10 : 5 : 85 (i.e. 100 μL DMSO stock solution → 50 μL Tween 80 → 850 μL Saline)
*Preparation of saline: Dissolve 0.9 g of sodium chloride in 100 mL ddH ₂ O to obtain a clear solution.
Injection Formulation 2: DMSO : PEG300 ：Tween 80 : Saline = 10 : 40 : 5 : 45 (i.e. 100 μL DMSO → 400 μLPEG300 → 50 μL Tween 80 → 450 μL Saline)
Injection Formulation 3: DMSO : Corn oil = 10 : 90 (i.e. 100 μL DMSO → 900 μL Corn oil)
Example: Take the Injection Formulation 3 (DMSO : Corn oil = 10 : 90) as an example, if 1 mL of 2.5 mg/mL working solution is to be prepared, you can take 100 μL 25 mg/mL DMSO stock solution and add to 900 μL corn oil, mix well to obtain a clear or suspension solution (2.5 mg/mL, ready for use in animals).

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Injection Formulation 4: DMSO : 20% SBE-β-CD in saline = 10 : 90 [i.e. 100 μL DMSO → 900 μL (20% SBE-β-CD in saline)]
*Preparation of 20% SBE-β-CD in Saline (4°C，1 week): Dissolve 2 g SBE-β-CD in 10 mL saline to obtain a clear solution.
Injection Formulation 5: 2-Hydroxypropyl-β-cyclodextrin : Saline = 50 : 50 (i.e. 500 μL 2-Hydroxypropyl-β-cyclodextrin → 500 μL Saline)
Injection Formulation 6: DMSO : PEG300 : castor oil : Saline = 5 : 10 : 20 : 65 (i.e. 50 μL DMSO → 100 μLPEG300 → 200 μL castor oil → 650 μL Saline)
Injection Formulation 7: Ethanol : Cremophor : Saline = 10： 10 : 80 (i.e. 100 μL Ethanol → 100 μL Cremophor → 800 μL Saline)
Injection Formulation 8: Dissolve in Cremophor/Ethanol (50 : 50), then diluted by Saline
Injection Formulation 9: EtOH : Corn oil = 10 : 90 (i.e. 100 μL EtOH → 900 μL Corn oil)
Injection Formulation 10: EtOH : PEG300：Tween 80 : Saline = 10 : 40 : 5 : 45 (i.e. 100 μL EtOH → 400 μLPEG300 → 50 μL Tween 80 → 450 μL Saline)

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Oral Formulation 1: Suspend in 0.5% CMC Na (carboxymethylcellulose sodium)
Oral Formulation 2: Suspend in 0.5% Carboxymethyl cellulose
Example: Take the Oral Formulation 1 (Suspend in 0.5% CMC Na) as an example, if 100 mL of 2.5 mg/mL working solution is to be prepared, you can first prepare 0.5% CMC Na solution by measuring 0.5 g CMC Na and dissolve it in 100 mL ddH2O to obtain a clear solution; then add 250 mg of the product to 100 mL 0.5% CMC Na solution, to make the suspension solution (2.5 mg/mL, ready for use in animals).

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Oral Formulation 3: Dissolved in PEG400
Oral Formulation 4: Suspend in 0.2% Carboxymethyl cellulose
Oral Formulation 5: Dissolve in 0.25% Tween 80 and 0.5% Carboxymethyl cellulose
Oral Formulation 6: Mixing with food powders

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Note: Please be aware that the above formulations are for reference only. InvivoChem strongly recommends customers to read literature methods/protocols carefully before determining which formulation you should use for in vivo studies, as different compounds have different solubility properties and have to be formulated differently.

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 (Please use freshly prepared in vivo formulations for optimal results.)