PLP-Dependent Cyclization and Decarboxylation
A PLP-dependent enzyme could certainly accomplish a reaction like this. An example of something similar is the PLP-dependent enzyme KAPA synthase in the biotin biosynthesis pathway. In that reaction, alanine is decarboxylated and a new bond is formed between the alpha carbon and an electrophilic thioester. Interestingly, the proposed mechanism involves deprotonation of the alpha carbon rather than decarboxylation as the initial step. Only after the new C-C bond is formed is the carboxylate lost:

1: Source: Webster, S.P, et al. (1998) Characterisation of S-amino-7-oxononanoate synthase: A bacterial PLP-dependent, acyl CoA condensing enzyme. Biochemical Society Transactions 26(3):S268. DOI: 10.1042/bst026s268
Although this is an intermolecular reaction, your proposed intramolecular reaction should be even easier to accomplish. An example of a PLP-dependent enzyme catalyzed reaction that results in intramolecular cyclization (but not decarboxylation) is that of aminocyclopropane carboxylate synthase.