Classification for β-lactamases: historical perspectives

ABSTRACT

Introduction

β-Lactamases are some of the most prevalent and well-studied families of enzymes, especially in the area of antibiotic resistance. Early attempts to categorize them used either functional names, such as penicillinase or cephalosporinase or structural designations into classes A and B. Increasing diversity of the properties of these enzymes has required a more expansive approach to nomenclature.

Areas covered

Historical designations for early β-lactamases relied heavily on functional names based on the biochemical properties of purified enzymes. As amino acid sequences began to be reported for a select group of these enzymes, classes of β-lactamases were defined, with a major lumping of enzymes into those that had active site serine residues (class A, C, and D) and those that were metallo-β-lactamases (MBLs or class B). More recent classification schemes, as determined through a Medline search, have attempted to incorporate both functional and structural features, using functional groups and subgroups to name β-lactamases within the same structural class. Nomenclature of these enzymes is now under the purview of the NCBI (National Center for Biotechnology Information).

Expert opinion

β-Lactamase nomenclature will continue to evolve with the identification of new enzymes and new functionalities.

KEYWORDS:

• Antibiotics
• β-lactamase
• nomenclature
• resistance
• structure
• function

Article highlights

• β-Lactamases have been named according to their functional activity or according to their amino acid sequence similarities.

• Molecular classifications of class A, B, C and D have been assigned to all β-lactamases that have amino acid sequences available.

• Functional classifications of groups 1, 2, 3, and 4, with appropriate subgroups, have been assigned primarily based on substrate and inhibitor profiles and experimentally-validated β-lactamase activity.

• Attempts to correlate both molecular and functional characteristics in a single set of nomenclature have been published.

Declaration of interest

The author has no relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending, or royalties.

Reviewer disclosures

Peer reviewers on this manuscript have no relevant financial or other relationships to disclose.

Author contributions

This manuscript was conceived of, researched by, written by and reviewed solely by the author.

Additional information

Funding

This paper was not funded.