Tigecycline

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Drug Name

Tigecycline is a glycylcycline antibiotic developed in response to the growing prevalence of antibiotic resistance in bacteria such as Staphylococcus aureus. It is the first clinically-available glycylcycline drug, a class of antibiotics derived from tetracycline. In susceptible bacteria, the drug inhibits protein synthesis by binding to the small ribosomal subunit and preventing them from accepting tRNAs in the A-site.

Table 1. Basic profile of tetracycline.

Description Broad-spectrum tetracycline antibiotic
Target(s) Ribosome (30S subunit)
Generic Tigecycline
Commercial Name Tygacil
Combination Drug(s) N/A
Other Synonyms N/A
IUPAC Name (4S,4aS,5aR,12aS)-9-[2-(tert-butylamino)acetamido]-4,7-bis(dimethylamino)-3,10,12,12a-tetrahydroxy-1,11-dioxo-1,4,4a,5,5a,6,11,12a-octahydrotetracene-2-carboxamide
Ligand Code in PDB T1C
PDB Structure 4yhh
ATC Classification J01AA12
RotateHydrogensLabels
Figure 1. 2D and 3D structures of Tigecycline (PDB ligand code: T1C).

Antibiotic Chemistry

Tigecycline was derived from an older tetracycline, minocycline, by adding a bulky adduct to the core ring structure (Peterson, 2008). This is the first of the class of novel glycylcycline-containing extended-spectrum antibiotics. The bulky adduct (Figure 2) overcame both efflux and ribosomal-type resistance (due to ribosomal mutations or protection).

Figure 2. 2D structure of Tigecycline, showing the four-ring core (marked by A-D) and the bulky adduct added to this molecule (highlighted in light yellow). The structure is drawn using ChemAxon.
Figure 2. 2D structure of Tigecycline, showing the four-ring core (marked by A-D) and the bulky adduct added to this molecule (highlighted in light yellow). The structure is drawn using ChemAxon.

Drug Information

Table 2. Chemical and physical properties (DrugBank).

Chemical Formula C29H39N5O8
Molecular Weight 585.65 g/mol
Calculated Predicted Partition Coefficient: cLogP 0.66
Calculated Predicted Aqueous Solubility: cLogS -3.1
Solubility (in water) 0.45 mg/mL
Predicted Topological Polar Surface Area (TPSA) 205.76 Å2

Drug Target

The ribosome is the macromolecular machine on which proteins are synthesized. It is targeted by many classes of antibiotics (including the tetracyclines) approved by the US FDA. Tigecycline, like tetracycline, positions itself in the decoding center of the 30S ribosomal subunit and makes direct contact with rRNA. It inhibits the accommodation of tRNAs in the A-site following EF-Tu-dependent GTP hydrolysis and as a result, prevents polypeptide chains from forming.

Learn more about protein synthesis, and the ribosome.

Drug-Target Complex

Each ribosomal subunit is composed of protein chains and rRNA. Here we view the structure of Thermus thermophilus 70S ribosome bound to mRNA, 2 tRNA molecules, and tigecycline (Jenner et al., 2013). The ribosome shown in Figure 3 is made up of
* 23S and 5S rRNA - colored blue
* 16s rRNA - colored pink
* tRNAs - shown in red and light green
* proteins - shown in cartoon representation in grey
* tigecycline - is shown in a yellow surface representation or in CPK (in the inset)

The primary binding site of tetracycline is within the decoding center in the 30S subunit. Its binding pocket, which is formed mostly by 16S rRNA, includes U1196 and a stacking interaction with C1054 (Figure 3).

Figure 3: Structure of 70s ribosome with tigecycline (PDB ID 4v9b, Jenner et al., 2013). The left image shows the 50S ribosomal subunit in blue and 30S in pink. The inset shows the interactions made at the primary binding site. The drug is shown in gray; key 16S rRNA nucleotides are shown in pink and green, and a Mg2+ ion is shown in light green.
Figure 3: Structure of 70s ribosome with tigecycline (PDB ID 4v9b, Jenner et al., 2013). The left image shows the 50S ribosomal subunit in blue and 30S in pink. The inset shows the interactions made at the primary binding site. The drug is shown in gray; key 16S rRNA nucleotides are shown in pink and green, and a Mg2+ ion is shown in light green.

The drug also forms several interactions with the hydrophilic side of the drug - including interactions with two Mg2+ ions and phosphate oxygens of the C1054, G1198 or one side and G966 on the other side (Jenner et al., 2013, see Figure 4). The most significant difference between tigecycline and tetracycline is the presence of 7-dimethylamido and 9-t-butylglycylamido moieties attached to ring D of tigecycline (marked with an arrow in the left side of Figure 4).

Figure 4. An alternative view of the interactions of tigecycline with 16S rRNA (PDB ID 4v9b, Jenner et al., 2013).
Figure 4. An alternative view of the interactions of tigecycline with 16S rRNA (PDB ID 4v9b, Jenner et al., 2013).

Pharmacologic Properties and Safety

Table 3. Pharmacokinetics: ADMET of tigecycline.

Features Comment(s) Source
Oral Bioavailability (%) 0 DrugBank
IC50 0.2 μM (for binding to Thermus thermophilus 30S ribosome subunit) (Jenner et al., 2013)
Ki (μM) N/A N/A
Half-Life (hrs) 27-43 hours DrugBank
Duration of Action ~12 hours FDA
Absorption Site Intestines DrugBank
Transporter(s) N/A N/A
Metabolism Tigecycline is not extensively metabolized by the liver. FDA
Excretion ~ 90% excreted via urine and feces FDA
AMES Test (Carcinogenic Effect) Probability 0.729 (non-AMES toxic) DrugBank
hERG Safety Test (Cardiac Effect) Probability 0.9926 (weak inhibitor) DrugBank
Liver Toxicity Cases of apparent liver injury are very rare. However, the mortality rate of tigecycline is relatively high compared to other antibiotics. The higher mortality rate seems to not be due to adverse events or liver injury but lower success or cure rates. LiverTox

Drug Interactions and Side Effects

Table 4. Drug interactions and side effects of tigecycline.

Features Comment(s) Source
Total Number of Drug Interactions 21 drugs Drugs.com
Major Drug Interactions aminolevulinic acid bcg bexarotene cholera vaccine, live typhoid vaccine, live Drugs.com
Alcohol/Food Interactions N/A N/A
Disease Interactions Colostridioides difficile associated diarrhea (CDAD) (major) Liver disease Drugs.com
On-Target Side Effects Reed streaks on skin, swelling, tenderness, or pain at the injection site Drugs.com
Off-Target Side Effects Cough or hoarseness, dizziness, fever or chills, headache, lower back or side pain, pain, warmth, or burning in the fingers, toes, legs, painful or difficult urination, vision or hearing problems Drugs.com
CYP Interactions CYP450 3A4 substrate DrugBank

Links

Table 5. Links to learn more about tigecycline.

Comprehensive Antibiotic Resistance Database (CARD) ARO:0000030
DrugBank DB00560
Drugs.com https://www.drugs.com/mtm/tigecycline.html
FDA - Tygacil https://www.accessdata.fda.gov/drugsatfda_docs/label/2013/021821s026s031lbl.pdf
LiverTox: National Institutes of Health (NIH) https://www.ncbi.nlm.nih.gov/books/NBK547888/
PubChem CID 54686904

Learn about tigecycline resistance.

References

DrugBank - Tigecycline https://go.drugbank.com/drugs/DB00560

Drugs.com - Tigecycline https://www.drugs.com/mtm/tigecycline.html

FDA - Tygacil https://www.accessdata.fda.gov/drugsatfda_docs/label/2013/021821s026s031lbl.pdf

Jenner, L., Starosta, A.L., Terry, D.S., Mikolajka, A., Filonava, L., Yusupov, M., Blanchard, S.C., Wilson, D.N., Yusupova, G. (2013) Structural basis for potent inhibitory activity of the antibiotic tigecycline during protein synthesis. Proc Natl Acad Sci U S A. 110(10):3812-6. https://doi.org/10.1073/pnas.1216691110

Jia, B., Raphenya, A. R., Alcock, B., Waglechner, N., Guo, P., Tsang, K. K., Lago, B. A., Dave, B. M., Pereira, S., Sharma, A. N., Doshi, S., Courtot, M., Lo, R., Williams, L. E., Frye, J. G., Elsayegh, T., Sardar, D. Westman, E. L., Pawlowski, A. C., Johnson, T. A., Brinkman, F. S., Wright, G. D., McArthur, A. G. (2017) CARD 2017: expansion and model-centric curation of the Comprehensive Antibiotic Resistance Database. Nucleic Acids Research 45, D566-573. https://doi.org/10.1093/nar/gkw1004

Peterson, L. R. (2008) A review of tigecycline--the first glycylcycline. Int J Antimicrob Agents. 32 Suppl 4:S215-22. https://doi.org/10.1016/s0924-8579(09)70005-6

PubChem - Tigecycline https://pubchem.ncbi.nlm.nih.gov/compound/54686904

March 2025, Helen Gao, Shuchismita Dutta; Reviewed by Dr. Gerard Wright
https://doi.org/10.2210/rcsb_pdb/GH/AMR/drugs/antibiotics/prot-syn/ribo/TCY/tigecycline