International Myeloma Working Group recommendations for global myeloma care.

Recent developments have led to remarkable improvements in the assessment and treatment of patients with multiple myeloma (MM). New technologies have become available to precisely evaluate the biology and extent of the disease, including information about cytogenetics and genetic abnormalities, extramedullary manifestations and minimal residual disease. New, more effective drugs have been introduced into clinical practice, which enable clinicians to significantly improve the outcome of patients but also pose new challenges for the prevention and management of their specific side effects. Given these various new options and challenges, it is important to identify the minimal requirements for diagnosis and treatment of patients, as access to the most sophisticated advances may vary depending on local circumstances. Here, we propose the minimal requirements and possible options for diagnosis, monitoring and treatment of patients with multiple myeloma.

Designing a metal-binding site in the scaffold of Escherichia coli KDO8PS.

KDO8PS (3-deoxy-d-manno-octulosonate-8-phosphate synthase) and DAH7PS (3-deoxy-d-arabino-heptulosonic acid-7-phosphate synthase) enzymes catalyse analogous condensation reactions between phosphoenolpyruvate and arabinose 5-phosphate or erythrose 4-phosphate, respectively. All known DAH7PS and some of KDO8PS enzymes (Aquifex aeolicus KDO8PS) require a metal ion for activity whereas another class of KDO8PS (including Escherichia coli KDO8PS) does not. Based on sequence alignment of all known KDO8PS and DAH7PS enzymes, we identified a single amino acid residue that might define the metal dependence of KDO8PS activity. One of the four metal-binding residues, a cysteine, is conserved only among metal-binding KDO8PS and DAH7PS enzymes and is replaced by an asparagine residue in other KDO8PS enzymes. We introduced a metal binding site into E.coli KDO8PS by a single N26C and a double M25P N26C mutation, which led to an increased k(cat) of the enzymes in the presence of activating Mn(2+) ions. The M25P N26C mutant of E.coli KDO8PS had a value of k(cat)/K(M) in the presence of Mn(2+) ions four times higher than A.aeolicus KDO8PS. KDO8PS and DAH7PS may have evolved from a common ancestor protein that required a divalent metal ion for activity. A non-metal-binding KDO8PSs may have evolved from an ancestor protein that was able to bind Mn(2+) but no longer required Mn(2+) to function and eventually lost one of metal-binding residues.