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metabion top-quality m-block Gene Fragments & Libraries

Accelerate your quality research and order your m-blocks DNA Fragments and m-block DNA Fragment Libraries from metabion.

What are m-block DNA Fragments?

Custom-made, uncloned, double-stranded (ds) DNA fragments assembled from top-quality metabion oligonucleotides.

metabion m-blocks are produced by overlapping synthetic oligonucleotides through annealing and elongation by a PCR-based technique to generate double-stranded (dsDNA) fragments. Sophistication of oligo building block design and quality of respective oligos to be assembled are key to arrive at high quality dsDNA fragments: m-blocks featuring low error rates for efficient correct full-length sequence screening.

Our standard m-Block specifications:

  • Sequence length 200 to 2000 bp
  • Standard DNA bases only
  • GC content 40 –70 %
  • Direct/ indirect repeats/ palindromic/ hairpin forming repeats < 25 nts
  • No repetitive elements longer than 20 nts within the first and last 35 bases of the sequence (5’ and 3’ ends)
  • Homopolimeric stretches no longer than 18 nts for A/T, and 12 nts for G/C
  • For additional flexibility, you can order m-blocks 5‘ phosphorylated (5′-phosphate group), or biotinylated (5´Biotin) on both strands
  • Standard quantity delivered: 1.000 ng; dry
  • Strict quality control by gel electrophoresis and Sanger sequencing

Our speciality: metabion’s m-block DNA Fragment Libraries

m-block DNA Fragment Libraries are m-blocks containing a number of wobble bases, ideal for recombinant antibody and protein engineering.

Wobbles are mixtures of 2 - 4 different bases (e.g. A/C; A/C/T; A/C/T/G) at a given position within the sequence. Our customized and individualized approach offers a maximum of flexibility regarding the positioning of wobbles, wobble ratios as well as their quantity (number of wobble positions within the designed and desired sequence).

By default, wobble bases are mixed in equal ratios before starting oligo-synthesis. For different ratios, please contact us.

Please use wobble IUPAC-IUB symbols, when ordering.

Our consulting service is free of charge and together with you, we will make it work.

Product Details

* Prices may vary when order is different to the above examples.

** TAT depends on the length and complexity of the m-blocks and, in some cases, may exceed the estimated time. Time required for production is the number of business days needed to undertake the synthesise of the product. Additional time will be required for the delivery of the product and dependent on the customers location.

Why m-blocks?

  • Simple and flexible - easily string together multiple fragments for larger constructs. No adapters to worry about. No restrictions for any downstream cloning method.
  • Time-efficient production to meet research deadlines.
  • Cost-effective and affordable.
  • High sequence fidelity – top quality, best value!


The assembly of double-stranded sequences from oligonucleotides is not trivial. Complexities in the desired sequences, like repetitive regions, a high or low GC-content or homopolymeric stretches can lead to misprimings and subsequently misassemblies.

Another challenge is the avoidance of single base deletions within the m-block sequence. m-block DNA fragments are “put together” using (on average) 60mer oligonucleotides. Oligos are the “critical component” for the process of producing ds DNA fragments. Critical with regard to sequence integrity. An optimal full-length versus n-1/n-x oligo sequence ratio is of the essence for achieving a large high-fidelity sequence population in the pool of assembled DNA fragments.

metabion has been optimizing synthesis processes for gene-synthesis grade oligonucleotides over the last 25 years, and pushed nt coupling efficiencies to the limit of what´s chemically possible and economically reasonable. An average of 99,6% (0,5% above industry standard) for 60mers still leaves us with a non-full-length portion of about 21% per oligo used for assembly, while applying industry standard of 99,1% coupling efficiency would result into a faulty sequence portion of double as much – 42%!

Needless to say, that error correction will be performed after m-block assembly applying a proprietary enzyme-based error correction method. However, the better the oligo-quality in the first place, the fewer errors need to be corrected, and the more efficient and complete error correction will be. This to ensure highest sequence integrity and fidelity of the final product – the assembled m-block DNA Fragments.

Quality control of metabion’s m-blocks include agarose gel-electrophoresis for size verification and evaluation of assembly success. Furthermore, all m-blocks are Sanger sequenced for sequence verification and fidelity.

For more information about m-blocks and ordering, contact us.

Crafted to suit diverse applications!

m-block Gene Fragments are crucial components in today´s life science research, serving various purposes.

They are used in applications such as enzyme engineering, antibody research and protein expression studies. Specifically, our m-block DNA libraries are very useful, well tested and proven for this field of application.

They also find direct application in experiments such as the creation of gRNA expression cassettes for CRISPR/Cas9-mediated gene editing, vaccine research, and various other biological research endeavours.

Moreover, they can serve as fundamental units for constructing larger dsDNA fragments, full-length gene constructs and even complete genomes.

m-blocks seamlessly integrate with various cloning and assembly kits, as well as automation platforms, and thus help streamlining integration of your desired sequences into your preferred cloning system.

Last but not least, m-block DNA Fragments serve MDx applications, e.g. as (q)pcr standards, positive controls or utilization in high resolution melting assays.

At metabion, we cater to your specific needs on an individualized level. Feel free to inquire about any special requirements including complex or difficult (i. e. repetitive) sequences, unnatural/modified bases or longer fragments.

Trust our expertise in Oligonucleotide- and Gene Fragment-Synthesis by ordering with confidence your customized m-block DNA Fragments and Libraries. We handle inquiries on a personalized basis.

For more information about m-blocks and ordering, contact us.