Database Description

ABCdb is a public resource devoted to the ATP-binding Cassette (ABC) transporters encoded by completely sequenced prokaryotic genomes. The ABC proteins are involved in a wide variety of physiological processes in Archaea, Bacteria and Eucaryota where they are encoded by large families of paralogous genes. The majority of ABC domains energize the transport of compounds across membranes. In bacteria, ABC transporters are involved in the uptake of a wide variety of molecules, as well as in mechanisms of virulence and antibiotic resistance. In eukaryotes, most of them are involved in drug resistance and in human cell, many are associated with diseases. Sequence analysis reveals that members of the ABC superfamily can be organized into sub-families, and suggests that they have diverged from common ancestral forms. A typical ABC transporter system is composed of an assembly of protein domains that serve different functions: i) two Nucleotide Binding Domains (NBD) that energize transport via ATP hydrolysis, ii) two Membrane Spanning Domains (MSD) that act as a membrane channel for the substrate, and iii) for the importer, a Solute Binding Protein (SBP) that confers substrates specificity on the transporter. The different partners of an ABC system are generally encoded by neighboring genes.

Recent Developments

In order to establish, in a complete genome, the repertory of ABC systems, we have to: i) identify the different partners, ii) assemble the partners in putative systems, and iii) classify the system into the correct functional subfamily (Quentin et al, 2002). The main pitfalls were the identification of loosely conserved domains and the assembly of partners encoded by genes dispersed over the chromosome. In order to face the avalanche of new sequenced genomes, we decided to enter into the databases the raw data issuing from this automatic procedure, before time consuming review by an expert. Therefore, the ABCdb database comprises two sections: CleanDb, for data checked by an expert and AutoDb for automatically annotated entries.

In this version, functional predictions are improved by the addition of references to Milton Saier's classification system of membrane transport proteins (, known as the Transporter Classification (TC) system.

Warning & disclaimer

By accessing this computer system you are consenting to system monitoring for law enforcement and other purposes. Unauthorized use of, or access to, this computer system may subject you to criminal prosecution and penalities. The information, opinions, data, and statements contained herein are not necessarily those of the CNRS and should not be interpreted, acted on or represented as such. The CNRS and its employees and contractors do not make any warranty, express or implied, including the warranties of merchantability and fitness for a particular purpose with respect to documents available from this server. In addition, the CNRS and its employees and contractors assume no legal liability for the accuracy, completeness, or usefulness of any information or process disclosed herein and do not represent that use of such information or process would not infringe on privately owned rights.

Reference herein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise, does not necessarily constitute or imply its endorsement, recommendation, or favouring by the CNRS or any of its employees or contractors.

Permission to reproduce documents from this server may be required.


The public database ABCdb is freely available by any individual and for any purpose, provided you give us credit. However, if you intend to distribute a modified version of one of our databases, you must ask us for permission first.


This work has been supported by grants from CNRS and ACI-IMPbio.