Publication Analysis 2009-2015 Modern protein research heavily depends on high-tech equipment and computer power. Research hot spots are in Martinsried, Heidelberg and Hinxton. Protein Research c Taavi.Ivan CC-BY-SA-3.0 P roteins are the workhorses in the cell – they transport car- go, they provide structural support, they communicate im- portant information. Although it’s clear that humans pos- sess about 25,000 genes, of which 20,000 are protein-coding, researchers disagree about the total number of proteins or the number of different polypeptides per cell. Thanks to alternative splicing and post-translation modifications, for instance, some re- searchers predict that a human cell could hold as much as 80,000 different polypeptides and two billion proteins in total. Sticking with superlatives, the current publication analysis in- tends to expose the most-cited protein researchers in Europe. But first, we’ll take a more general look at the best-performing na- tions in this discipline. As we did earlier, for this part of the anal- ysis, we had to restrict our sources to those journals that spe- cifically publish protein research. Protein papers, however, of- ten end up in biochemistry or molecular biology journals, which have a rather wide scope, including genetic studies, for instance. For this reason, we decided to exclude some prominent journals in the field, the likes of EMBO Journal or The FASEB Journal . This may explain the low number of publications in our nations’ per- formance table. This restriction, however, was abrogated for the most-cited authors ranking. Surprisingly strong Spain Germany takes the lead position with more than 80,000 total citations, far ahead of England with about 50,000 citations. With regard to the citation-per-article ratio, one nation is as good as the other (18.3 vs 18.6). Astonishingly, Spain in third position is only slightly behind England, regarding total citations, and ahead of both Germany and England, when it comes to average cita- tions per paper. As expected, Eastern Europe, a stronghold of an- alytical sciences, performs well in protein research, with Poland in 12 th place, the Czech Republic in 14 th place and Russia occupy- ing the 16 th spot. Leaders in the citations-per-article category are Denmark (22.0), Switzerland (21.6) and The Netherlands (20.4). Compared with their US colleagues, European protein research- ers again wrote more papers, gathering more citations, but on av- erage, articles, reviews and proceedings papers from the USA re- ceived more attention aka citations. Let’s move on to the top papers in the field. Four of the five most-cited publications revolve around bioinformatics tools and databases. Thus, the paper in second place introduces the Clustal Omega programme, developed by scientists at the Conway In- stitute in Dublin, which allows the alignment between three or more protein sequences ( www.ebi.ac.uk/Tools/msa/clustalo ) . Publications in third and fourth place describe the Pfam protein families’ database ( http://pfam.xfam.org ). Founded in 1995 by Erik Sonnhammer, Sean Eddy and Richard Durbin, the latest ver- sion of the database, version 31.0, contains a total of 16,712 fami- lies and 604 clans. The fifth most-cited publication in protein re- search is all about the Search Tool for the Retrieval of Interact- ing Genes/Proteins, STRING ( https://string-db.org ) . This data- base comprises all known and predicted protein-protein interac- tions, be it direct (physical) or indirect (functional) associations. Version 10.0 contains information on more than nine million pro- teins from about 2,000 organisms. Modifications most-cited Only the most-cited paper in protein research, with well over 3,000 citations, is not about computational tools and databas- es. Amongst others Matthias Mann, Chuna Ram Choudhary and Jesper Olsen analysed, by high resolution mass spectrometry, ly- sine acetylation of proteins. These post-translational modifica- tions steer many cellular processes, such as chromatin remodel- ling and splicing. The team identified 3,600 lysine acetylation sites on 1,750 proteins. All three authors, Mann (1 st ), Choudhary (21 st ) and Olsen (6 th ), made our top 30 – thanks in large to this article. Here, we should mention a few limitations of this ranking. First, we only included researchers, who are interested in more general aspects of proteins or protein families. Second, publication of those re- searchers, who combine their protein studies with, for instance, work on genes or epigenetics (see Peer Bork, 2 nd , or Christian von Mering, 7 th ) must contain a significant amount of the keywords “protein”, “peptide” or “proteomics”. By the way, when compil- ing our top 30 list, we were reminded of the benefits of having a ResearcherID. In more than one case, we would have missed a few papers (and citations) because the researcher’s name was misspelled in the Web of Science database. Without further ado, let’s look at the most-cited protein re- searchers in Europe in more detail. Remarkable is a clear geo- graphic clustering: The Max Planck Institute (MPI) for Biochem- istry in Martinsried, Germany, and the European Molecular Biol- ogy Labs in Heidelberg, Germany, and Hinxton, UK, are premium research hubs for protein research. Not less than five scientists among our top 30 are affiliated with the MPI for Biochemistry. One of them is our ranking’s number one, Matthias Mann, expert in mass spectrometry proteomics. He identified and quantified the first model proteome (yeast) and, according to his Institute, is the first German researcher with an h-index higher than 200.