Biology subjects

Serrano, D.

Publications and source records attributed to Serrano, D..

3 recordsLinked to original sources

bioRxiv2026

Evidence for an Organometallic Species Formed in the ArsL Reaction

The radical S-adenosylmethionine (SAM) superfamily comprises over 800,000 unique sequences of enzymes that catalyze more than 100 distinct reactions. Canonical radical SAM (RS) enzymes are composed of a full or partial triose phosphate isomerase fold and contain a highly conserved CX3CX2C motif. The cysteines in the conserved motif ligate an [Fe4S4] cluster used in the reductive cleavage of SAM to yield methionine and a 5'-deoxyadenosyl 5'-radical (5'-dA*). The 5'-dA* is typically used to initiate catalysis by abstracting a hydrogen atom from a bound substrate, yielding 5'-deoxyadenosine and a substrate radical. ArsL, a recently characterized RS enzyme involved in the biosynthesis of the antibiotic arsinothricin (AST), catalyzes a reaction that deviates from the canonical RS reaction, forming methylthioadenosine and a 3-amino-3-carboxypropyl radical (ACP*). The ACP* is used to construct a carbon-arsenic bond to form the organoarsenic compound hydroxyarsinothricin (AST-OH), the penultimate enzymatic step in forming AST. While investigating how ArsL suppresses the formation of the 5'-dA* in favor of the ACP*, we discovered that ArsL forms a unique organometallic species containing a bond between the gamma carbon of ACP and the unique iron of the [Fe4S4] cluster. We propose that ArsL uses this novel species to generate a sufficiently electrophilic carbon that can be attacked by arsenous acid, thereby forming the carbon-arsenic bond.

biochemistry↗

bioRxiv2023

Host space, not energy or symbiont size, constrains feather mite abundance across passerine bird species

Comprehending symbiont abundance among host species is a major ecological endeavour, and the metabolic theory of ecology has been proposed to understand what constraints symbiont populations. We parameterized metabolic theory equations to predict how bird species body size and the body size of their feather mites relate to mite abundance according to four potential energy (microbial abundance, uropygial gland size) and space constraints (wing area, number of feather barbs). Predictions were compared with the empirical scaling of feather mite abundance from 26,604 birds of 106 passerine species, using phylogenetic modelling and quantile regression. Feather mite populations were strongly constrained by host space (number of feather barbs) and not energy. Moreover, feather mite species body size was unrelated to their abundance or to the body size of their host species. We discuss the implications of our results for our understanding of the bird-feather mite system and for symbiont abundance in general.

ecology↗

bioRxiv2022

Population-specific association of Clock gene polymorphism with annual cycle timing in stonechats

Timing is essential for survival and reproduction of organisms across the tree of life. The core circadian clock gene Clk has been implicated in annual timing and shows highly conserved sequence homology across vertebrates except for one variable region of poly Glutamine repeats. Clk genotype varies in some species with latitude, seasonal timing and migration. However, findings are inconsistent, difficult to disentangle from environmental responses, and biased towards high latitudes. Here we combine field data with a common-garden set up to study associations of Clk with latitude, migration and annual-cycle timing within the stonechat species complex with trans-equatorial distribution range. Including 950 individuals from nine populations with diverse migratory strategies. Gene diversity was lowest in resident African and Canary Island populations and increased with latitude, independently of migration distance. Repeat length and annual-cycle timing was linked in a population-specific way. Specifically, equatorial African stonechats showed delayed timing with longer repeat length for all annual-cycle stages. Our data suggest that at low latitudes with constant photoperiod, Clk genotype might orchestrate a range of consistent, individual chronotypes. In contrast, the influence of Clk on annual-cycle timing at higher latitudes might be mediated by its interactions with genes involved in (circadian) photoperiodic pathways.

genetics↗