As a professional in the field of oligonucleotide supply, I’ve witnessed firsthand the significant role temperature plays in maintaining the integrity and performance of oligonucleotides. Oligonucleotides, short sequences of nucleic acids, are essential tools in various biological and medical applications, including PCR, gene sequencing, gene therapy, and diagnostic assays. Understanding the effects of temperature on their stability is crucial for ensuring their quality and efficacy, both during storage and experimental use. Oligonucleotide
The Chemical Structure of Oligonucleotides and Temperature Sensitivity
Oligonucleotides are composed of nucleotides linked by phosphodiester bonds. Each nucleotide consists of a nitrogenous base, a pentose sugar, and a phosphate group. The nitrogenous bases – adenine (A), thymine (T) (or uracil (U) in RNA), cytosine (C), and guanine (G) – form the genetic code and are held together by hydrogen bonds in a double – stranded structure, following the base – pairing rules (A – T/U and C – G).
The stability of these hydrogen bonds and the overall oligonucleotide structure is highly temperature – dependent. At low temperatures, the hydrogen bonds between complementary bases are relatively stable, allowing the oligonucleotides to maintain their double – stranded or secondary structures. However, as the temperature rises, the kinetic energy of the molecules increases, causing the hydrogen bonds to break. This process is known as denaturation.
Effects of Temperature During Storage
Low – Temperature Storage
Low – temperature storage, typically at – 20°C or even – 80°C, is the standard practice for long – term preservation of oligonucleotides. At these low temperatures, the chemical reactions that can lead to degradation are significantly slowed down. The reduced kinetic energy of the molecules minimizes the chances of hydrolysis of the phosphodiester bonds, which can break the oligonucleotide chain.
Moreover, low temperatures help maintain the integrity of the secondary structures. For example, hairpin loops or other intramolecular base – pairing structures are less likely to be disrupted. This is particularly important for oligonucleotides used in applications such as aptamer – based assays, where the specific secondary structure is crucial for binding to target molecules.
However, it’s important to note that repeated freeze – thaw cycles can be detrimental to oligonucleotide stability. Each cycle of freezing and thawing subjects the oligonucleotides to physical stress. As the solution freezes, ice crystals can form, which can physically shear the oligonucleotide chains. To minimize this risk, it is recommended to aliquot oligonucleotide stocks into smaller volumes, so that only the necessary amount is thawed for each use.
Room – Temperature Storage
In some cases, short – term storage at room temperature may be unavoidable. Oligonucleotides are relatively stable at room temperature for a short period, typically a few days. But over time, the increased kinetic energy at room temperature accelerates various degradation processes.
Hydrolysis of the phosphodiester bonds becomes more likely, leading to a shortening of the oligonucleotide chains. Oxidation of the bases can also occur, especially for guanine, which is particularly susceptible to oxidation. Oxidized bases can affect the hybridization properties of the oligonucleotides, leading to reduced efficiency in PCR or other hybridization – based assays.
Effects of Temperature During Experimental Use
PCR and Annealing Temperatures
In polymerase chain reaction (PCR), temperature is a critical parameter. The PCR process involves three main steps: denaturation, annealing, and extension. During the denaturation step, the double – stranded DNA template is heated to a high temperature (usually around 94 – 98°C) to break the hydrogen bonds and separate the two strands.
The annealing step follows, where the oligonucleotide primers bind to the complementary sequences on the single – stranded DNA template. The annealing temperature is carefully optimized based on the melting temperature (Tm) of the primers. The Tm is the temperature at which half of the oligonucleotide – template duplexes are in a double – stranded state and half are single – stranded. If the annealing temperature is too high, the primers may not bind efficiently to the template, resulting in low PCR yields. Conversely, if the annealing temperature is too low, non – specific binding of the primers can occur, leading to the amplification of unwanted DNA fragments.
Hybridization Assays
In hybridization assays, such as Southern blotting or microarray analysis, the temperature also affects the specificity and efficiency of hybridization. High temperatures promote the dissociation of mismatched base pairs, increasing the specificity of the hybridization. However, if the temperature is too high, even the perfectly matched base pairs may dissociate, reducing the signal intensity.
Impact of Temperature on Oligonucleotide Modifications
Many oligonucleotides used today are modified to enhance their stability, binding affinity, or other properties. These modifications can also be affected by temperature.
For example, phosphorothioate – modified oligonucleotides, which have a sulfur atom replacing one of the non – bridging oxygen atoms in the phosphodiester bond, are more resistant to nuclease degradation. However, at high temperatures, the sulfur – containing bonds may undergo chemical changes, potentially altering the biological activity of the oligonucleotides.
Fluorescently labeled oligonucleotides, which are widely used in real – time PCR and fluorescence in situ hybridization (FISH), can also be affected by temperature. High temperatures can cause photobleaching of the fluorescent dyes, reducing the intensity of the fluorescent signal.
Temperature – Induced Aggregation of Oligonucleotides
At certain temperatures and ionic conditions, oligonucleotides can form aggregates. Aggregation is more likely to occur at low temperatures or in the presence of high concentrations of salts. Aggregated oligonucleotides can cause problems in experimental applications. In PCR, for example, aggregated primers may not be able to bind efficiently to the template, leading to reduced amplification efficiency.
To prevent aggregation, it may be necessary to adjust the temperature and ionic strength of the solution. Heating the oligonucleotide solution briefly to a high temperature (e.g., 95°C) and then slowly cooling it can sometimes disrupt the aggregates and restore the oligonucleotides to their monomeric forms.
Ensuring Oligonucleotide Stability at Different Temperatures
As an oligonucleotide supplier, we take several measures to ensure the stability of our products at different temperatures. During manufacturing, we use high – quality raw materials and strict quality control procedures to minimize impurities that could catalyze degradation reactions.
We also provide detailed storage and handling instructions to our customers. Our oligonucleotides are typically shipped on dry ice to maintain a low temperature during transit. For long – term storage, we recommend storage at – 20°C or lower. We also offer advice on how to handle thawed oligonucleotides to minimize degradation.
In addition, we are constantly researching and developing new formulations and stabilization techniques to improve the stability of our oligonucleotides at a wider range of temperatures. This includes the use of additives that can protect the oligonucleotides from hydrolysis and oxidation.
Conclusion
Temperature has a profound impact on the stability of oligonucleotides, affecting their chemical structure, secondary structure, and biological activity. Whether during storage or experimental use, careful consideration of temperature is essential for ensuring the quality and performance of oligonucleotides.
As an experienced oligonucleotide supplier, we understand the importance of providing high – quality, stable oligonucleotides to our customers. Our knowledge and expertise in temperature – related stability issues allow us to offer products that meet the rigorous demands of modern biological and medical research.
API If you are in need of high – quality oligonucleotides for your research or diagnostic applications, we invite you to contact us for a detailed discussion on your specific requirements. We are committed to providing you with the best products and services to support your scientific endeavors.
References
- Saiki, R. K., Gelfand, D. H., Stoffel, S., Scharf, S. J., Higuchi, R., Horn, G. T., et al. (1988). Primer – directed enzymatic amplification of DNA with a thermostable DNA polymerase. Science, 239(4839), 487 – 491.
- Meier, C., & Diederichsen, U. (2014). Oligonucleotides: Antisense Inhibitors of Gene Expression. In H. Liang & A. Wong (Eds.), Nucleic Acid Therapeutics: Principles, Strategies, and Applications. Springer New York.
- Kierzek, R., & Turner, D. H. (1991). Prediction of RNA secondary structure. In J. E. Dahlberg & J. A. Gerbi (Eds.), RNA Processing. Academic Press.
Zhejiang Hengkang Pharmaceutical Co., Ltd.
Zhejiang Hengkang Pharmaceutical Co., Ltd. is well-known as one of the leading oligonucleotide manufacturers and suppliers in China. With a professional production team, we are able to meet the needs of the majority of our customers. Please feel free to wholesale bulk high quality oligonucleotide from our factory.
Address: No.11 Chengen Road, Pubagang Town, Sanmen County, Zhejiang Province, China.
E-mail: commercial@hengkangpharm.cn
WebSite: https://www.hengkang-pharm.com/
