Nucleic Acids Research, 2007, Vol. 35, Database issue D355 Figure 1. Navigation tree and report page for the hypothetical secreted protein of Helicobacter pylori (gi_15645712). This figure also illustrates the application of association rule mining for finding potential annotation errors (see text). A number of domain assignments have been marked as suspicious. The InterPro domain IPR001440 and PFAM domain PF00515 were erroneously assigned to this gene product based on a weak similarity hit to a single TPR_1 repeat whereas the domain definition requires at least three repeat copies. Note that all other features marked as suspicious are in fact annotated correctly; the method does not detect annotation errors as such, but rather incompatible feature combinations which might include annotation errors. location, General properties and Export) and lists the analysis results for a particular gene product, which are also available for download in different formats. The DNA and Protein viewers have been completely re-designed. They can be extensively customized and are now based on dynamic panel architecture. The protein viewer displays several panels for various types of evidence that can be conﬁgured by selecting ‘preferences’ in the top panel. For example certain panels can be hidden, resized and the color scheme can be changed. The DNA viewer allows for easy navigation along the chromosomes and is capable of displaying an unlimited number of features at different zoom levels. Any PEDANT3 dataset can be searched using sequence IDs, sequences, PROSITE-like patterns or free text as the query option. PEDANT Web Services Web Services technology is becoming increasingly popular within the bioinformatics community as a means to exploit the large amounts of data, software programs and computing power available at various institutions (4,5). According to the World Wide Web Consortium (W3C) a Web Service is a software system designed to support interoperable machine- to-machine interactions over a network (http://www.w3.org/ 2002/ws/). This technology is based on the eXtensible Markup Language (XML) and open standards, and is plat- form and programing language independent. This enables clients for a particular service to be written in many lan- guages, such as Java or Perl, irrespective of the language the service was written in. A Web Service has an interface that is described in a machine processable format using the XML based Web Services Description Language (WSDL). WSDL provides a format for the description of a Web Service interface, includ- ing parameters and data types in sufﬁcient detail for a pro- gramer to write a client application for that service. Tools are available for various programing languages to generate the required client classes, such as Apache Axis’s WSDL2Java (http://ws.apache.org/axis/java/user-guide.html). The client