Gold nanoparticles (AuNPs) exhibit unique properties that have made them a very attractive material for application in biological assays. Given the potentially interesting interactions between AuNPs and biological macromolecules, we investigated AuNPs-induced protein crystal growth. Differently functionalized AuNPs were tested as additives in cocrystallization studies with model proteins (hen egg white lysozyme (HEWL), ribonuclease A (RNase A), and proteinase K) as well as with case studies where there were problems in obtaining well-diffracting crystals. Trials were performed considering different crystallization drawbacks, from total absence of crystals to improvement of crystal morphology, size, twinning, and number of crystals per drop. Improvement of some of these factors was observed in the cases of HEWL, RNase A, phenylalanine hydroxylase (PAH), myoglobin, native aldehyde oxidase (AOH), and human albumin. In these proteins, the presence of the AuNPs promoted an increase in the size and/or better crystal morphology. From the systematic trials and subsequent observations, it can be concluded that the introduction of AuNPs should definitely be considered in crystal optimization trials to improve previously determined crystallization conditions.

• Premise of the study: Three species of the mangrove tree genus Rhizophora are found in the New World and along the west coast of Africa. Of these, R. mangle is the most abundant and has a complex interbreeding relationship with the sympatric R. racemosa and R. harrisonii. The development of additional microsatellite markers would permit paternity analyses and investigation of the hybrid origin of these species.• Methods and Results: Using an enriched library method, via hybridization with biotinylated oligonucleotides complementary to repetitive poly AG/TC, primers for 11 microsatellite markers of R. mangle were developed and characterized in populations in Pará and São Paulo (Brazil) and Florida (USA). Ten of these markers were transferable to R. racemosa and R. harrisonii.• Conclusions: The microsatellite markers presented here will be useful in studies of contemporary and historical gene flow between American and West African Rhizophora species.

Understanding the specific molecular interactions between proteins and β1,3‐1,4‐mixed‐linked d‐glucans is fundamental to harvest the full biological and biotechnological potential of these carbohydrates and of proteins that specifically recognize them. The family 11 carbohydrate‐binding module from Clostridium thermocellum (CtCBM11) is known for its binding preference for β1,3‐1,4‐mixed‐linked over β1,4‐linked glucans. Despite the growing industrial interest of this protein for the biotransformation of lignocellulosic biomass, the molecular determinants of its ligand specificity are not well defined. In this report, a combined approach of methodologies was used to unravel, at a molecular level, the ligand recognition of CtCBM11. The analysis of the interaction by carbohydrate microarrays and NMR and the crystal structures of CtCBM11 bound to β1,3‐1,4‐linked glucose oligosaccharides showed that both the chain length and the position of the β1,3‐linkage are important for recognition, and identified the tetrasaccharide Glcβ1,4Glcβ1,4Glcβ1,3Glc sequence as a minimum epitope required for binding. The structural data, along with site‐directed mutagenesis and ITC studies, demonstrated the specificity of CtCBM11 for the twisted conformation of β1,3‐1,4‐mixed‐linked glucans. This is mediated by a conformation–selection mechanism of the ligand in the binding cleft through CH‐π stacking and a hydrogen bonding network, which is dependent not only on ligand chain length, but also on the presence of a β1,3‐linkage at the reducing end and at specific positions along the β1,4‐linked glucan chain. The understanding of the detailed mechanism by which CtCBM11 can distinguish between linear and mixed‐linked β‐glucans strengthens its exploitation for the design of new biomolecules with improved capabilities and applications in health and agriculture.DatabaseStructural data are available in the Protein Data Bank under the accession codes 6R3M and 6R31.

Dipteryx odorata is an intensely exploited Amazonian tree legume. Microsatellite markers were developed to study the genetic structure, gene flow and reproductive biology of D. odorata. Eight highly polymorphic microsatellite markers were isolated from enriched repeat libraries screened for microsatellite repeats. An average of 16 alleles and 0.964 phenotype diversity per locus were found in 76 individuals from the Tapajos National Forest, in the state of Pará in the Brazilian Amazon.