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Short answer
Golden Gate assembly (also called Golden Gate cloning) joins several DNA fragments in one tube using a Type IIS restriction enzyme and a DNA ligase together. Because the enzyme cuts outside its recognition site, each fragment end carries a designer 4-nucleotide overhang, so fragments join in a chosen order and the recognition sites are lost from the finished product. It was described by Engler, Kandzia and Marillonnet in 2008.
Definition and scope
Golden Gate is a restriction-ligation cloning method, not a vendor product. The original paper, A One Pot, One Step, Precision Cloning Method with High Throughput Capability (PLOS ONE 3(11):e3647), used the Type IIS enzyme BsaI. A Type IIS enzyme cuts DNA a fixed distance away from its recognition sequence, so the overhang it leaves can be any sequence the designer picks. This differs from the conventional enzymes covered in the restriction enzyme digest setup guide, which cut inside their recognition sites and leave overhangs fixed by the enzyme.
This page covers the concept and design logic. It is general background for researchers and lab staff, not a bench protocol: reaction volumes, cycling programmes and kit instructions belong to the supplier or lab SOP you are following. For the wider picture of how inserts and vectors are combined, see gene cloning.
How Golden Gate assembly works
Per Engler et al. (2008), the restriction enzyme and the ligase act at the same time in one tube. Three properties make the method work:
- Designer overhangs. The enzyme cuts outside its site, so a 4-nucleotide overhang can be chosen freely and used to specify which fragment end meets which.
- Self-selection. Correctly joined products no longer contain the enzyme’s recognition sites and so are stable. Other ligation products, such as a re-formed original vector, still carry the sites and are cut again.
- Speed and efficiency. The authors reported that a 5-minute restriction-ligation produced close to one hundred percent correct recombinant plasmids in their tests, with constructs of two and three inserts demonstrated.
The paper also notes that no recombination site remains at the junction. The only sequence that must be present is the 4-nucleotide overhang itself, which fixes one amino acid if the junction falls inside a coding region. Other Type IIS enzymes used in this family of methods include BsmBI and BbsI (BpiI recognises the same site as BbsI); enzyme names are listed in the restriction enzyme name index.
Golden Gate cloning and Golden Gate assembly: same method
The two phrases are used interchangeably in the literature and by suppliers. “Assembly” tends to be used when several parts are joined; “cloning” when an insert goes into a vector. Both refer to the one-pot Type IIS approach above.
MoClo and GoldenBraid: Golden Gate as a standard
Basic Golden Gate joins a set of parts once. Two 2011 PLOS ONE papers turned it into reusable, hierarchical standards.
MoClo (Modular Cloning)
Weber et al. (PLOS ONE 6(2):e16765) defined standard module types (promoters, 5′ UTRs, signal peptides, coding sequences, terminators) with defined fusion sites. Modules are combined into level 1 transcription units and then into level 2 multigene constructs. The authors demonstrated a 33 kb construct containing 11 transcription units assembled from 44 modules in three cloning steps, and expressed from one to 13 units in Nicotiana benthamiana. They also reported that efficiency falls as the number of units joined in one step rises, and the largest assembly needed optimised cycling.
GoldenBraid
Sarrion-Perdigones et al. (PLOS ONE 6(7):e21622) proposed GoldenBraid as an iterative system in which every assembled product can serve as an input to the next round. It alternates two plasmid levels, α and Ω, whose Type IIS sites sit in inverted orientations and which carry different resistance markers for counterselection, so the cycle can repeat. The authors demonstrated a 14.3 kb construct with 19 parts in five transcriptional units. Their stated main limit is the size and stability of DNA the host plasmid can carry. They contrast it with MoClo: GoldenBraid uses two enzymes and binary assembly, while MoClo also uses BbsI and intermediate levels with end-linker cassettes.
Design checklist from the primary sources
| Design point | What the source says | Source |
|---|---|---|
| Internal recognition sites | Remove internal sites in the parts, for example with primers carrying a single-nucleotide (often silent) mismatch. Alternatives are sequential digestion and ligation with heat inactivation between, or a second Type IIS enzyme. | Engler et al. 2008 |
| Overhang choice | A 4-nucleotide overhang gives 256 possible sequences; the 16 palindromic ones are best avoided, leaving 240 usable. | Engler et al. 2008 |
| Vector | The vector backbone should not contain additional recognition sites for the enzyme used. | Engler et al. 2008 |
| PCR-derived parts | Sequence clones made from PCR products to confirm them. | Engler et al. 2008 |
| Number of parts per step | Efficiency decreases as more units are joined in one step. | Weber et al. 2011 |
| Reuse of products | Plain Golden Gate products could not be reused in standardised higher-level assembly; GoldenBraid adds alternating α/Ω levels to allow it. | Sarrion-Perdigones et al. 2011 |
Digital design of the overhangs and a record of the final construct are usually handled in plasmid design software; see the plasmid map guide for what a map should record.
Where it matters in the lab
Golden Gate suits work in which many parts must be combined in a defined order, or the same part library is reused across many constructs, which is why MoClo and GoldenBraid were built as standards for plant synthetic biology. Per the sources, the enzyme (for example BsaI), the ligase and the part and vector collection all have to match the chosen standard.
Common misunderstandings
- “Scarless” does not mean “no sequence at the junction”. The method leaves no recombination site, but the 4-nucleotide overhang remains and can fix an amino acid in a coding region (Engler et al. 2008). Designs that need a specific junction must plan the overhang accordingly.
- Not every enzyme works. The method needs a Type IIS enzyme; conventional enzymes cut within their site and cannot give free overhangs.
- Efficiency claims are conditional. The near-100% figure came from the authors’ tests with two and three inserts; the MoClo authors report lower efficiency as unit numbers grow.
FAQ
What is the difference between Golden Gate assembly and Gibson Assembly?
Golden Gate uses Type IIS enzymes with ligase and designer 4-nucleotide overhangs, and the recognition sites are removed from the correct product. Gibson Assembly is a separate, overlap-based method that this page does not cover.
Which enzymes are used?
The original method used BsaI. BsmBI and BbsI (BpiI) are other Type IIS enzymes used in the same family; the MoClo paper uses BbsI alongside BsaI, and GoldenBraid uses two enzymes.
What is GoldenBraid?
An iterative Golden Gate-based standard from 2011 that alternates α and Ω plasmid levels so that assembled products can be reused as inputs.
How are primers or overhangs designed?
Choose non-palindromic 4-nucleotide overhangs from the 240 usable sequences, make sure parts have no internal recognition sites, and keep the backbone free of extra sites. Specific primer layouts are given in the paper or supplier protocol you follow.
Sources
- Engler C, Kandzia R, Marillonnet S. A One Pot, One Step, Precision Cloning Method with High Throughput Capability. PLOS ONE 3(11):e3647, 2008. journals.plos.org (read 2026-11-08).
- Weber E, Engler C, Gruetzner R, Werner S, Marillonnet S. A Modular Cloning System for Standardized Assembly of Multigene Constructs. PLOS ONE 6(2):e16765, 2011. journals.plos.org (read 2026-11-07).
- Sarrion-Perdigones A et al. GoldenBraid: An Iterative Cloning System for Standardized Assembly of Reusable Genetic Modules. PLOS ONE 6(7):e21622, 2011. journals.plos.org (read 2026-11-08).
